What are Microgreens?

The term ‘microgreen’ defines a juvenile or a nascent stage in the life of a fully grown plant. Microgreens are very similar to sprouts, the difference being that they are grown in light, not darkness. They, like sprouts, can be grown on a small scale as a hobby at home or as small or large commercial operations. The basic difference in all the above-mentioned varieties is the duration and method of harvesting. The microgreen phase of a plant is when it starts forming its first set of leaves. Also known as 'vegetable confetti', the tiny, delicate, and very young microgreen leaves are used as an essential ingredient in salads and other foods as garnishing or as a taste enhancer. The tuft-like appearance of microgreens makes them an unusual visual and culinary delight. The flavourful and highly nutritious greens grow up to 2 inches tall within as little as 6 days.

Microgreens are more nutritionally dense than the regular greens. They are replete with flavour, taste, and nutrition! Scientific evidence has proved microgreens to be 40 times more nutritive than the leaves of the same mature plant, grown using the normal potting and harvesting methods. Microgreens pack in a considerably higher percentage of the following nutrients: Vitamin C, E, and K. Lutein and beta-carotene (even more than the carrots!) can be found in abundantly large proportions in Microgreens. Not just loaded but overloaded with five times more carotenoids and micronutrients, microgreens are indeed a superfood that grows fast and provides a burst of health and beauty all at the same time!

Seed selection and Sowing

Some common seeds include red amaranth, arugula, beets, borage, cabbages, chards, cress,

Kales, Mizuna, Mustards, Pak Choi, purslanes, radishes, sorrel, and others. Check Appendix 1 for elaborate seeds list.

Purchase seeds specifically listed for use as microgreens, as they are not treated with fungicides. Since they are not treated, they may have fungal spores and/or bacterial spores on their surface. These pathogens must be eliminated by surface sterilization to prevent them from causing death of the germinating seedlings. If different seedlings need to be combined in the same tray, select varieties having the same growth rate. Do not combine seeds that germinate quickly with those that germinate slowly. For example, radish is ready to harvest in 5–6 d, whereas some lettuce and other greens may take 7–10 d. Some useful combinations include purple and Diakon radishes, amaranth and all greens, amaranth and spicy greens, and Komatsuna (green or red) with wildfire lettuce.

Seeding densities should be thick enough to cover the tray, but not to the point of inhibiting air flow. Both small and large seeds should be sown thickly, then gently tamped into the growing medium/mat/towel. As a rule of thumb, sow small seeds at a density of approximately 10–12 seeds per square inch of tray surface, and larger or medium-sized seeds at a density of 6–8 seeds per square inch.

Surface sterilization of the seeds before placing them on the paper towels or capillary matting is critical to success. Use a 10% bleach solution (1 part bleach to 9 parts water) in a plastic cup to swirl the seeds around for 3–4 min; then rinse with raw water using a household strainer.

Key growing information

Culture

Microgreens should be grown in a protected area like greenhouse or indoor grow room. Since, the growing period is limited to a week or less, they should be given maximum protection as there won’t be time for any corrective measures in case of pest or disease like Mold. Mild sunlight or

Watering

Moisten the paper towels or mat with some raw water and then place the seeds from the strainer into the tray with a spoon and spread evenly around the surface using the spoon or clean fingers. When adding raw water for the first 3 d until the seed germinates, be careful to pour the water slowly along the edge of one end of the tray so that the seeds do not float. Commercial growers choose to either circulate the water to the bottom of the tray or implement a mist spray to provide even moisture.

After germination and the seeds have grown into the paper towels or mat (usually 3 d), start using a dilute nutrient solution (half the normal recommended strength when growing same plant for full growth). Nutrient concentrates can be purchased from Hydrilla store. Harvest the seedlings after 7–10 d using a pair of scissors to cut off the shoots as the roots are not consumed.

Lighting, Temperature and Humidity

Similar to any other germination rules, keep away from light until germination. If using LED lights choose moderate intensity of around 30 W and place the lights about 12 in. (30 cm) above the tray. Operate the lights for 12–14 h/d. provide a moderate temperature of around 24 C until germination and then reduce it to 16 C to 18 C. High temperature inhibits germination and also can increase disease after germination. Sufficient air circulation can be provided with fans to prevent pest and disease issues.

Diseases

Since Microgreens are densely planted, they are prone to diseases like mold due to damping off, poor air circulation, saturated media/mat, high temperature and humidity condition.

Harvest

Microgreens can be harvested anywhere between 1 to 2 weeks based on the variety. They are usually harvested couple of days after true leaves appear. They usually reach a height of ½” to 2”. The majority of vegetable varieties grown as microgreens are ready for harvest in less than 2 weeks, though the brassicas mustard and radish have a faster growth rate and therefore mature faster than beets, carrots, or chard. Herbs grown as microgreens tend to be comparatively slow-growing, maturing in 16–25 days. Depending upon types, varieties, and environmental conditions, a production cycle can be prolonged up to 4 weeks and beyond. They have to be cut at the shoots as the roots are not consumed. Use clean sterilized scissors to cut to prevent any disease infection. They can also be sold as live produce without cutting the roots. The weight of the product might increase but this also increases shelf life.

Packaging and storage

They can be packed in clamshell boxes and their shelf life ranges from 5 to 10 days under proper storage conditions. They are nutritious best when consumed immediately on harvest.

Yield data

Many factors come into play when evaluating microgreens yield. The two most obvious are seeding density and plant size at harvest (days to maturity). Even small changes to these factors can alter yield quantities. Then add natural vs. supplemental light, inside growing vs. greenhouse growing, seasonal shifts, variations in equipment and materials, etc. Want a larger plant? Use a bit less seed and wait a few more days. Want to harvest at the cotyledon stage? Sow more thickly and harvest earlier. Always be sure to provide sufficient air flow and appropriate temperatures to support your plants. Give importance to taking good notes. To replicate or alter the results of any given seeding, you need to be able to see clearly what was done before. Sowing dates and quantities of seed sown should be based upon customer demand, delivery schedules, and varietal growth rates. As noted, different varieties grow at different rates. Keep records and modify your system as needed. With some trailing, good record-keeping, and repetition, a grower can become adept at estimating seed requirements versus project yield, timing production cycles, and forecasting ROI.

Marketing

Marketing topic is mostly addressed last in any guide however market research should be given the top priority. Few tips here:

1. Before going into production, get in touch with potential buyers possibly superstores selling microgreens, oriental restaurant owners or chefs, etc.
2. Produce few mixed varieties and distribute samples and take feedback. Feedback collected from chefs is very useful.
3. Once you finalize the varieties, sort them as per their growth period and sow them separately.
4. Modify your product varieties to keep customers engaged.
5. Keep your produce and deliver it fresh. Keep the nutrition promise.

Appendix 1: List of microgreen seeds

1. Amaranth, Garnet Red
2. Corn Microgreen Seeds
3. Yellow Carrot Microgreens Seeds
4. Mizuna Green Microgreen Seeds
5. Garden Cress Microgreen Seeds
6. Sunflower Microgreen Seeds
7. Radish Purple Microgreens
8. Green Mustard Microgreen Seeds
9. Wheatgrass Microgreen Seeds
10. Coriander microgreen seeds
11. Alfalfa microgreen seeds
12. Clover microgreen seeds
13. Peas microgreen seeds
14. Kohl Rabi Purple microgreen seeds
15. Parsley microgreen seeds
16. Kale microgreen seeds
17. Basil Purple microgreen seeds
18. Basil Green Microgreen seeds
19. Kohl Rabi Green Microgreen Seeds
20. Beet Root Microgreen Seeds
21. Pak Choi Microgreen Seeds
22. Amaranthus Red Microgreen Seeds
23. Radish Pink Microgreen Seeds
24. Radish White Microgreen Seeds
25. Onion Microgreen Seeds
26. Broccoli Microgreen Seeds
27. Spinach Microgreen Seeds
28. Cabbage Microgreen Seeds
29. Cauliflower Microgreen Seeds
30. Fenugreek (Methi) Microgreen Seeds
31. Red Chard Microgreen Seeds
32. Red Cabbage Microgreen Seeds
33. Red Kale Microgreen Seeds
34. Rocket Microgreen Seeds

The challenges and potential of aquaponics production is still an unexplored area of study in  India. Aquaponics is a combined method of farming by bringing aquaculture and hydroponics together in a single system. There has been a positive change in Aquaponics farming as the popularity of the system increased in the last few years in our country.

By 2050, the world’s population is estimated to increase to 9 billion. The expansive numbers of people are expecting to rely on agricultural sector including farming, fisheries, woodcrafts, and livestock. Natural calamities and crisis affect millions of people who depend on the primary sector. For reducing poverty and attaining food security, expansion of agriculture sector is the most efficacious means. Small farmers are the major contributors to the World’s food, but they are the poorest people in the developing countries. 70 per cent of the people living in the rural area depends on Agriculture even today, however, one-fourth of the population find it difficult to meets their daily nutritional requirement.

Indian farmers are exposed to many challenges resulting from low agricultural growth, sustainability concerns, and land degradation, as a large area of farmland has become infertile due to the overuse of fertilizers and pesticides. Conventional farming methods because of large usage of fertilizers for growing crops degraded the quality of the soil and local water sources. It is high time to overcome these challenges through innovative farming methods. The technological and scientific advancement in the field of agriculture has opened a new era for the design and development of modern devices for plant health monitoring. Aquaponics farming is a solution to overcome some of these challenges to an extent if the farmers are able to maintain the system with proper care and technical support.

Although aquaponics has received considerable attention in foreign countries, Indian farmers are relatively new to this system. However, there has been a gradual increase in awareness of this system over the past few years in the country.

Aquaponics is an integrated method of growing fishes and crops in a re-circulating system. In other words, it is an integrated system of re-circulating aquaculture and hydroponics in one production system. Water from the fish tank that contains fish excretes cycles through grow beds where plants are grown, which is nutritious for the plant's growth and plants' filter the water flowing into the fish tank to keep the fish healthy. The main elements for aquaponics are the fish tank and grow beds with a small pump that filters water between the two. The success of an aquaponics system requires proper maintaining of the plants, fish, and nutrients that gives a well-balanced and interdependent relationship. Aquaponics farming is suitable for farmers who have fewer land holdings and in areas where water is scarce. Crops grown in aquaponics have less damage and are able to grow in denser climate.

In India, the land holdings used for agriculture are limited to less than 0.2 hectares. As a result, the small-scale agriculturists aim to maximize production within the minimum resources. Growing awareness of consumers on the excessive use of fertilizers and pesticides are leading to a trend that favours organic farming. The interest of the young generation to produce vegetables and other regional cultivations on a small scale within the available land area has further boosted the scope of organic farming. Organic farming is a concept with considerable thrust on integrated systems wherein a major part of inputs required for farming is raised within the system. Integrated farming uses wastages and sub-products of a particular cultivation for the use of other. It usually includes growing and breeding of cattle, duck, fish etc. This is a globally accepted technology and adapted to a greater extent by the Indian farming community. Within the available space that includes terrace and balconies of apartments, Indian households have started taking up aquaculture in small tanks along with vegetables in separate grow beds. The method of recycling wastewater and making it available for further use has increased its demand all over this time. Integrating hydroponics (the method of growing plants without soil) and aquaculture has been given more importance in the current agricultural scenario.

As the aquaponics system has many advantages and increases the productivity within a short time period, it has gained popularity in several states of India in recent times. State Fisheries Departments are promoting aquaponics by providing training programmes and technical support to the farmers. It is an effective means of growing food that helps to maintain sustainability, as it requires only 10 per cent of water and no use of chemical fertilizers as compared to the traditional farming method.

Aquaponics as a commercial venture is evolving in India. People are discovering it as a promising avenue to rely upon as a dependable source of livelihood. Further, small and medium-sized units are more efficient in managing costs and realizing higher net income per unit area compared to large units. However, a variety of factors such as lack of training, inadequate technical guidance, ignorance of market pricing and uncertainties about the market demand of the product, are some of the reasons for incurring losses. These challenges can be overcome by providing technical sessions about the working of the system and by making consumers aware of the benefits of organic products. In Hydrilla workshops, apart from taking participants through Aquaponics farming methods, fish and plant health management, system design aspects, we take through the analysis of marketing strategies like identifying right crops based on market demand, direct selling to neighbourhood consumers, indirect selling to wholesalers, restaurants and grocery stores.

In general, the success of aquaponics farming relies upon the local markets, climatic and geographical conditions. An important feature of aquaponics systems is their ability to reduce the local impacts that arise from the nutrient discharges. Due to the dynamic characteristics of the aquaculture industries, it is expanding rapidly in recent times. Hence, more emphasis should be given on high productivity, intensive systems with similar low global impacts rather than focusing completely on the reduction of local impacts.

Aquaponics has immense potential to be the forerunner in the next phase of sustainable aquaculture.

The first step in Hydroponics farming is to understand the difference between soil fertilizers, and the requirements of plants. Most growers are aware of soil fertilizers such as those called by numbers 19-19-19 and 20-20-20, but what does 20-20-20 really mean?

Does it mean 20% Nitrogen (N), and 20% Phosphorous (P), and 20% Potassium (K) is the N.P.K ratio?

No, it’s not that simple.

It’s, 20% Nitrogen (N) and 20% Phosphorous Pentoxide (P2O5) and 20% Di-Potassium Oxide (K2O). (Depending on the country of origin, these units change by continent)

This translates to the actual % of the N.P.K as follows.

20% Nitrogen (N), 8.8% Phosphorous (P), and 16.6% Potassium (K).

However, a good Hydroponic nutrient contains all of these plus all the other minerals required for healthy growth. They will also be in the correct ratio to each other, according to plant type, and stage of growth, e.g. Vegetative, flowering or fruiting stage. 

The minerals required for good growth are as follows:

There are other minerals found in plant tissue when analysed, but for our purposes, these are the main requirements for Hydroponic growing, and the ones we have to monitor.

Hydroponics grower has to understand and make sure that the Hydroponics nutrients being used have all the above macro and micronutrients needed by the plant in a proportion that is needed at various stages of growth.

Take for example, the above 20-20-20 fertilizer with 20% Nitrogen (N), 8.8% Phosphorous (P), and 16.6% Potassium (K).

Researchers have determined that a tomato plant in fruiting stage needs more Potassium than Nitrogen with N:K ratio of even 1:3. Using 20-20-20 fertilizer for tomato crop in the fruiting stage might not give the best yield when compared to a Hydroponic nutrient modified in a proportion to suit the crop need.

Hydroponic farming gives best results only when the grower gives nutrients in the right proportion suiting crop, stage of growth, water pH, EC, climate conditions etc.

• Hydroponic is the act of raising plants without using soil, but rather in a water medium with nutrients.
• The plants are placed in a hydroponic system that supplies the required nutrients to the roots with the help of the water medium.
• The use of hydroponic has helped farmers to evade serious seedling diseases and pests like fungus and gnats, which mostly attack in moist soils.
• Media like coconut fibre, plugs, and peat pots have necessary nutrients and ensure that the seeds have a healthy growth.
• Rockwool or oasis can serve as a medium, the seedlings can be transplanted along with the cube into a complete hydroponic system later.
• Rapid rooters are mostly used as a medium as they have large numbers of important microbes and Mycorrhizal fungi that help in colonizing the root thus maximizing uptake of nutrients by the plant and evade serious diseases.

Other options:-

• Other than rapid rooters, there are other hydroponic options you can go for like, rock wool, coconut fibre, peat and oasis cube.
• While the rapid rooters retain a lot of water, oasis and coir retain very little water.
• The rock wool has a high PH concentration; therefore, the cubes should be rinsed in the solution of both water and vinegar to neutralize the PH before putting the seeds in the cubes to grow.
• Mix a teaspoon of vinegar in a cup half-filled with water and dip the cubes into the resulting solution shaking off the excess.
• Rock wool needs more attention because it is alkaline in nature.

Location: -

• The container should be placed where it can receive maximum light.
• If you choose to grow your seeds in the house, the convenient places are like on a table or near a window where there is partial light either in the morning or in the afternoon.
• In case you want to grow outside, then you should select a partially sunny location like a porch.
• The container should be away from heavy rainfall and winds.
• Since the container is small and portable, it should be moved from one place to another to protect it from bad weather.

Maintenance: -

• Water should be added only when the cubes start to get dry. Because much water favours the development of molds on the rock wool.
• On the other hand, if there is no water for a long time the seeds will not germinate. Thus, the cubes should be moist but not wet or dry.
• When the seedlings reach 2 inches in height, add diluted nutrient solution or fish water to the water in the container. This will greatly boost the root growth.

Transplanting: -

• The seedlings are ready for transplanting to a hydroponics grow system when they reach 3-4 inches in height. Look for 3 to 4 true leaves.
• Fill the net pot with clay pellets until it is half full. Which supports the plants.
• The best time of day to plant is in the late afternoon when the sun is not hot, and the wind has calmed down. By taking advantage of this time of day, the new plants have overnight to acclimate.
• Strong sun and wind are very hard on new transplants. Unless watered carefully, and in some cases provided with some shelter from the wind and sun, they can severely wilt.
• This places the plants under stress at the very beginning of their growing cycle and is not a good idea because sometimes they never bounce back and don’t thrive as well as they could have.

Growing peppers in aquaponic units: There are many varieties of peppers, all varying in colour and degree of spice, yet from the sweet bell pepper to the hot chili peppers (jalapeno or cayenne peppers) they can all be grown with aquaponics. Peppers are more suited to the media bed method but they might also grow in 11 cm diameter NFT pipes if given extra physical support.

Growing conditions: Peppers are a summer fruiting vegetable that prefers warm conditions and full sun exposure. Seed germination temperatures are high: 22–34 °C. Seeds will not germinate well in temperatures 30–35 °C lead to floral abortion or fallout. In general, spicier peppers can be obtained at higher temperatures. The top leaves of the plant protect the fruit hanging below from sun exposure. As with other fruiting plants, nitrate supports the initial vegetative growth (optimum range: 20–120 mg/litre) but higher concentrations of potassium and phosphorus are needed for flowering and fruiting. 

Growing instructions: Transplant seedlings with 6–8 true leaves to the unit as soon as night temperatures settle above 10 °C. Support bushy, heavy-yielding plants with stakes or vertical strings hanging from iron wires pulled horizontally above the units. For red sweet peppers, leave the green fruits on the plants until they ripen and turn red. Pick the first few flowers that appear on the plant in order to encourage further plant growth. Reduce the number of flowers in the event of excessive fruit setting to favour the growing fruits to reach an adequate size. 

Harvesting: Begin harvesting when peppers reach a marketable size. Leave peppers on the plants until they ripen fully by changing colour and improve their levels of vitamin C. Harvest continually through the season to favour blossoming, fruit setting and growth. Peppers can be easily stored fresh for 10 days at 10 °C with 90–95 per cent humidity or they can be dehydrated for long-term storage.

pH: 5.5–6.5

Plant spacing: 30–60 cm (3–4 plants/m2, or more for small-sized plant varieties)

Germination time and temperature: 8–12 days; 22–30 °C (seeds will not germinate below 13 °C)

Growth time: 60–95 days

Temperature: 14–16 °C night time, 22–30 °C daytime

Light exposure: full sun

Plant height and width: 30–90 cm; 30–80 cm

Recommended aquaponics method: media beds

Reference: http://www.fao.org/3/a-i4021e.pdf

Cherry Tomato: - 

Tomatoes are an excellent summer fruiting vegetable to grow using all available methods although physical support is necessary.

A higher nitrogen concentration is preferable during the early stage to flower stage. However, potassium should be present from the flowering stage to fruit setting to growth.

Tomatoes are rich in vitamins A and C, low in calories and a source of lycopene (the “Red” in tomatoes), which has been tapped as a cancer-fighting agent.

If you have experience in growing tomato you know that to get the high-quality products and good yields with a limited space can be quite a challenge.

We’ll try to consolidate all important things that you need to know if you want to grow tomatoes, have high-quality products and great yields in your greenhouse. We’ll also share our experience and you’ll see great benefits of aquaponic systems for profitable commercial tomato production.

Tomato is one of the most demanded vegetables. In the season but also out of the season. It is used as a fresh produce but also an input for the production of many different products like sauces. One of the greatest advantages is that it grows in the air and we can use a lot of greenhouse height for our production.

The main advantages of growing tomatoes in protected spaces (greenhouses) compared to other crops are:

• It is highly attractive and demanded product
• We can have very high yields per sqm
• There are many hybrids that are resistant to diseases.

Growing Conditions: -

• When you have set up your aquaponic system and decided to grow tomato you need to pay attention to some details. If you make mistakes, in the beginning, you will not see problems usually until it’s too late to fix them.

1. Type of aquaponic system?
2. How to band tomatoes for the best vertical growth?
3. How to make tomato grow faster?

• Each and every part of the aquaponic system that is not synched to specific natural laws can create problems in the future. These problems can be insignificant but sometimes these problems can lead to total disaster. For that reason, it is important to have all the information and to understand each part of the system.
• The first and most important factor is to choose the right aquaponic system for tomato production.
• Out of all aquaponic systems, BED system is probably the most convenient for many types of crops. But it is not a profitable system. Because it is quite robust, it takes a lot of space and is quite expensive to construct.
• For profitable tomato cultivation, one of the best aquaponic systems is DUTCH BUCKET

• In Dutch bucket aquaponic system we are using a number of buckets for growing our crops in them. In buckets, we put any growing media that is suitable for aquaponics. When we are irrigating crops the water is moving through growing medium and feeding the root of our plants.
• We need to make sure that there is always some water in the bottom of the bucket.
• We can achieve this by drilling drainage holes on a certain height of the bucket. For this system to work we do not need any additional siphons.
• When constructing Dutch bucket aquaponic system pay special attention to the following

1. Greenhouse space usage
2. Pipes and nozzle clogging
3. Space for roots development
4. Bucket drainage

• Tomatoes prefer warm temperatures with full sun exposure. Below 8-10°C, the plants stop growing, and night temperature 13-14 encourage fruit set. Temperature above 40°C cause floral abortion and poor fruit setting.
• Tomatoes have a moderate tolerance to salinity, which makes them suitable for areas where pure freshwater is available. However, higher salinity at fruiting stage improves quality of the products.

Planting Instructions: -

• Set stakes or plant support structures before transplanting to prevent root damage.
• Transplant the seedlings into units 3-6 weeks after germination when the seedling is 10-15 cm and when the night time temperatures are constantly above 10°C.
• In transplanting the seedlings, avoid waterlogged conditions around the plant collar to reduce any risk of diseases.
• Once the tomato plants are about 60 cm tall, start pruning the unnecessary upper branches. Remove the leaves from the bottom to 30cm of the main stem for better air circulation and reduce fungal incidence.
• Remove the leaves covering each of the fruiting branches soon before ripening to favour nutrition flow to the fruits and to accelerate maturation.

Harvesting: -

• Most cherry tomato plants will start flowering in about a month. Flowers will be followed by tiny green fruits. After a few weeks, those turn into full-blown cherry tomatoes you can harvest.
• A truly ripe cherry tomato will come off its stem very easily and is well worth waiting an extra day for, so hold off on picking them until they're ripe. Then, pluck individual fruits every day for best results. With luck, your plant will continue to produce right up until winter. If the weather turns unseasonably cool or an early frost threatens, you can tuck an old sheet over and around the plant to extend your harvest season.
• Fruits can be easily maintained for 2-4 weeks at 5-7°C under 85-90 percentage relative humidity.

Tips: -

• PH: 5.5-6.5
• Plant spacing: 40-60cm (3-5 plants/sqm)
• Germination time and temperature: 4-6 days and 20-30 °C
• Growth time: 50-70 days till the first harvest; fruiting 90-129 days up to 8-10 months.
• Optimal temperature: 13-16°C night, 22-26 °C day
• Light exposure: full sun
• Recommended methods: Media Beds and DWC

• Growing hydroponics lettuce is one of the easiest and the best ways to start hydroponic gardening.
• Lettuce is a simple to grow all round plant that can ensure you get great results when grown in soil, as long as you keep pests off it.
• This is where growing lettuce hydroponically will make perfect sense and will be a terrific first task for any hydroponic setup.
• Lettuce hydroponics will typically look after themselves and do not need a lot of nutrients as other heavy feeding plants like tomatoes.
• It’s obviously still a great practice to check out your growing hydroponic lettuce plants every day for pests or other problems, though these problems are considerably decreased with hydroponics, particularly indoor hydroponics.
• Actually, the only issue you could come across when growing hydroponic lettuce at home is size.
• Lettuce is in high demand and has a high value in urban and peri-urban zones, which makes it a very suitable crop for large-scale commercial production.

Note: -

• Check lettuce for signs of downy mildew, powdery mildew or gray mold and get rid of any infected plants.
• Water that’s heavily chlorinated can lead to issues with lettuce. You should use lightly chlorinated city water or well water.

Lettuce varieties: -

Lettuce can be characterized based on their leaf and head formation.

Crisp head or iceberg: -

• Crisp head lettuce, more commonly known as iceberg, has a tight head of crisp leaves. Often found in the local salad bar, it is actually one of the most difficult lettuce varieties to grow. This lettuce variety is not fond of hot summer temperature or water stress and may rot from the inside.
• Start iceberg lettuce via seed directly sown 18-24 inches apart or started indoors and then thinned 12-14 inches between heads. Some iceberg lettuce varieties include Ballade, Crispino, Ithaca, Legacy, Mission, Salinas, Summertime and Sun Devil, all of which mature in 70-80 days.

Romaine or Cos: -

• Romaine varieties are typically 8-10 inches tall and upright growing with spoon-shaped, tightly folded leaves and thick ribs. Colouration is medium green on the exterior to a greenish white inside with the outer leaves.
• Sometimes being tough whilst the interior foliage is tender with wonderful crunch and sweetness. Different types of this lettuce are Brown Golding, Chaos Mix black, chaos Mix white, Devil’s Tongue, Dark green Romaine, De Morges Braun, Hyper Red Rumple, Little Leprechaun. All of which mature within around 70 days.

Butterhead, Boston or Bibb: -

• One of the more delicate varieties of lettuce, Butterhead is creamy to light green on the inside and loose, soft and ruffled green on the exterior. These different types of lettuce may be harvested by removing the entire head or just the outside leaves and easier to grow than crispheads, being more tolerant of conditions.
• Less likely to bolt and rarely bitter, the butterhead lettuce varieties mature in about 55-75 days and spaced similarly to the crispheads. These varieties of lettuce include Blushed Butter Oak, Buttercrunch, Carmona, Divina, and Yugoslavian red.

Growing Conditions: -

• Lettuce is a winter crop. For head growth, the night air temperature should be 3-12°C, with a day temperature of 17-28°C.
• The generative growth is affected by photoperiod and temperature extended daylight warm conditions(>18°C) at night cause bolting. Water temperature >26°C may also result in bolting and leaf bitterness.
• The plant has low nutrient demand; however higher calcium concentrations in water help to prevent tip burn in leaf in summer crops.
• The ideal PH is 5.8-6.2. but lettuce still grows well with a PH as high as 7, although some iron deficiencies might appear owing to reduced bio-availability of this nutrient above neutrality.

Growing instructions:

• Seedlings can be transplanted in units at three weeks when plants have at least 2-3 true leaves. Supplemental fertilization with phosphorous to the seedlings in the second and third weeks favours root growth and avoids plant stress at transplant.
• Take care not to damage the roots of plants during transplanting because such damage will make the plant susceptible to disease infection.
• It is advisable to transplant the plant in the late afternoon to prevent them becoming stressed in the heat of the day under high UV conditions.
• The transplant will begin to adapt to the new location at night and roots will start to grow into the solution below.
• Make sure the plants base is touching the flow of nutrient solution below when transplanting.
• To achieve crisp sweet lettuce, grow plants at a fast pace by maintaining high nitrate levels in the unit. When air and water temperatures increase during the season, use bolt -resistant(summer) varieties. If growing in media beds, plant new lettuces where they will be partially shaded by taller nearby plants.

Lighting: -                                      

• Lettuce grows up vigorously with fluorescent lighting. It would obviously grow far better with the more expensive lighting specially created for hydroponics, like HID and some of the latest LED grow lights for indoor plants.
• However, regarding cost-effectiveness, from the viewpoint of the small-scale grower, fluorescent lighting is the best.
• These are cool weather crops, so too much heat can, in fact, delay germination.

Harvesting Hydroponics lettuce: -

Hydroponics harvesting depends on the following factors

• First, this will depend on what type you are growing. Romaine takes up to 85 days. Bibb and Loose-leaf lettuce can take 45 to 55 days.
• It has to do preference, growing lettuce indoors then you have to manage the environment and prolong your harvest.
• The majority of hydroponic lettuce production systems created around two ideas, either the floating raft system or the nutrient flow technique (NFT) system.
• The floating raft method is of particular interest since it is very affordable and can produce a lot of hydroponic lettuce.
• One of the major issues with raft systems is that the hydroponic lettuce nutrients solution is continually stagnant and will require that you use pumps to circulate water and produce important aeration.
• If the roots are not getting the precious oxygen, floating raft systems experience substantial loses of crops in the form of nutrients.

Below are some types that work well in hydroponics and with indoor artificial lighting:

• Royal Oakleaf is a darker green variety of lettuce that does extremely well in hydroponic growing systems and is also resistant to heat.
• Tango grows perfectly in cooler environmental only.
• Red Fire is a deep red, loose leaf variety that’s ideal for both warm and cool climates.
• Green Ice is a variety of green loose that offers a long picking season.

Hydroponic romaine lettuce also does well though it usually takes a little bit longer to attain maturity.

Tips: -

• When you harvest lettuce with the roots attached, it will prolong storage life by two to four weeks.
• To prevent getting water mold such as Pythium or Phytophthora in your hydroponic lettuce system, use bleach to sanitize the tray between plants. If the lettuce gets infected, the plant is a loss.

What is pH?

pH is a measure of the relative concentration of hydrogen ions (H+) to hydroxide ions (OH-). The greater the number of H+ ions in relation to OH- the more acidic the solution becomes. The greater the ratio of OH- ions to H+, the more basic the solution becomes. PH is measured on a scale of 1-14. A reading below 7 means that there are more H+ ions and a reading above 7 indicates more OH- ions. At pH 7 there are the same number of H+ ions as OH- ions so the pH is neutral, neither acid nor base.

Acids and Bases

Any substance that increases the concentration of hydrogen ions (lowers the pH) when added to water is called an acid. A substance that reduces the concentration of hydrogen ions (raises the pH) when added to water is called a base or an alkali. Some substances enable solutions to resist pH changes when an acid or base is added. These substances are called buffers. Buffers are very important in helping to maintain a relatively constant pH in a feeding solution and in the root zone after the water has been applied to the crop. Most greenhouse water supplies have sufficient alkalinity that they require routine acid addition to correct the pH to the normal 5.8-6.2 feeding range. At this level, the irrigation water tends to have a neutral effect on media pH, although this depends on the buffering capacity of the media. Some growers use very pure water from rain and surface sources. In these situations, they may need to apply a combination of acid and base materials to stabilize and buffer the pH.

Why does pH Matter?

Improper management of media pH can result in poor growth and reduced plant quality in greenhouses and nurseries. The pH or soil reaction has a primary influence on the solubility and availability of plant nutrients. Many crops have a narrow range of pH tolerance. If the pH of the soil medium falls above or below this tolerance zone, they may not grow properly due to nutrient deficiency or toxicity.

The availability of most fertilizer elements is affected to some extent by the media pH. Calcium and magnesium become more available as the pH increases, while iron, manganese, and phosphorus become less available. A one-unit pH drop can increase the solubility of manganese by as much as 100 times, and the solubility of iron by as much as 1000 times.

Why Adjust Irrigation pH?

By carefully modifying the pH and alkalinity of your irrigation and feed solutions, you can help maintain the desired plant growth and quality. There are other reasons to monitor and control pH in your irrigation water and nutrient solutions: 1) Solution pH affects the availability of nutrients. 2) Correct pH helps ensure dissolved fertilizer concentrates remain in solution when mixed in the water supply. 3) Acid injection can be used to neutralize excess alkalinity in water supplies.

Understanding The pH Scale

The pH scale measures the relative concentration of Hydrogen Ions (H+) and Hydroxyl ions (OH-) in a solution. Technically, the pH of a solution is defined as a negative logarithm of the hydrogen ion concentration. The ‘p’ is the mathematical symbol for a negative logarithm and the ‘H’ is the symbol for hydrogen. The pH scale measures this, and places a value on it ranging from 0 to 14. Since it is a log scale, each number on the scale is 10 times greater (or smaller) than the next. A lower pH number corresponds to a higher concentration of hydrogen ions (H+) relative to hydroxyl ions (OH-). A higher pH number corresponds to a relatively lower concentration of hydrogen ions

Measuring pH

There are several methods available for measuring pH, but the most useful and practical is an accurate pH meter. Follow the instructions included to preserve the accuracy and life of your instrument. These meters typically use a liquid filled glass probe, although some are now using flat sensor technology.

Water and nutrient solution samples can be measured directly or preferably after a few hours of settling time. Dissolved CO2 in water supplies can cause slightly lower readings until the sample has come to equilibrium with the air. When testing media, freshly mixed samples of media should be watered and allowed to stand for 24 hours before a reading is taken to release some of the lime and fertilizers. The preferred method for testing media pH is to obtain several representative samples of a crop and to measure each separately. Multiple measurements give greater accuracy in reading, and shows the degree of variability of pH across several locations. A saturated media extract or a 1:1 soil to distilled water ratio is fine for measuring media pH.

Factors Affecting pH

These variables can affect the final pH, the rate of pH change, and the amount of modifying action required. They include the effects of:

• Soil temperature
• Fertilizer materials (may raise, lower or buffer pH)
• Soil amendments such as gypsum, sulfur and lime
• Root volume & metabolic activity
• Soil microorganisms
• pH and alkalinity of the irrigation water
• Leaching fraction
• Buffering capacity of both the soil medium and the irrigation source
• Media cation exchange capacity