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Grow light guide for indoor farming - hydroponics

Some people are asking us for grow light guides based on crops that are grown hydroponically.

This blog post will be edited and updated. 


Microgreens key info

Mature size: 2.5 to 7.5 cm (1 to 3 inches)
Growth cycle: 10-12 days
Seed: day 0
Germinate: day 1 to 4
Grow: day 4 to 10
Harvest: day 10-12
Light requirements: 80 to 100 μmol/m2/s
Photoperiod: 8 to 12 hours per day
Temperature: 21°C (70°F)
Relative Humidity: 40-60%
Closest distance from fixture: 10 to 20cm (2.9 to 7.8 inches)
Hydroponic water EC/PPM: 0.6 to 1.0
Hydroponic water pH range: 6.0 to 6.5

How to grow microgreens

For a full guide regarding microgreens see also this blog.
Microgreens are essentially seedings and the easiest the grow from all crops. They take about 10 to 12 days to grow. To germinate they need warmth and moisture, when they start to develop leafs they need more airflow and light. Some people use regular tap water and no nutrients. Others use an EC of about 0.6 to 1.0 EC and pH of about 6.0 to 6.5 which is similar to tap water. You can use a seedling tray or deep water culture system. Since Microgreens are small, grow fast and need little light, they are a perfect crop for growing indoor and in shelfs.


Microgreens need a bit of light, they need light to photosynthesise from about day 4 to 10. Light can make them stronger, tastier and give them a more vibrant color. You would need about 80 to 100 μmol/m2/s on the leaf. Make sure your lights have some distance to the leaf as it would otherwise create leaf-burn. The Nurser 3 is a perfect fixture for growing microgreens with the right intensity and spread across the greens.

Difference that light can make

Some people grow microgreens without any plant-centric light, what you will see is that the microgreens will be a more lanky, weaker and bleaker. With light you would see the microgreens to grow up straight, with thicker stems and thicker leaves and a darker color. If you’re new to plant-centric light, this crop is a perfect crop to experience with in an A/B experiment. e.g. sow microgreens in a tray and put tray A in front of a windowsill and put tray B under HortiPower light. What differences would you see and taste?


Basil has a refreshing, peppery and sweet flavor that everyone loves. It is believed to be a powerful adaptogen or anti-stress agent and is believed to regulate hormones responsible for inducing happiness and energy. It grows well under grow lights and it is a favorite plant in herb-gardens.

Basil key info

Mature size: About 45-60cm tall and wide (18-24 inches)

Growth cycle: 40-50 days

Seed: day 0

Germination: 7-10 days

Transplant: 3-5 weeks

Harvest: 8-10 weeks

Light requirements: 100 to 300 μmol/m2/s

Photoperiod: 10 to 18 hours per day

Temperature: 21°C to 29°C (70°F to 84°F)

Relative Humidity: 60-70%

Closest distance from fixture: 5-10cm (2-4”)

Hydroponic EC/PPM: 1.6-2.2

Hydroponic pH range: 6.2-6.8, it depends on the seed supplier e.g. Johnny's Seeds suggest 5.8 to 6.2

How to grow Basil

Growing this fragrant and delicious plants is rewarding. Basil loves pruning and toping, as it will enable the plant to grow new stems and branches to add to height and mass. Pruning on top will make the basil plant to grow in volume. It is tempting to cut basil leaves from the bottom, but you’d better start from the top and you’ll see lush growth. If you see flowers you should cut them off to have a longer vegetative phase.


Basil is a light loving crop, they love outdoor sunlight and indoor growth light. If you’re using HortiPower Nurser 3, keep them on for about 10 to 18 hours per day and with the lights about 5-10cm (2-4”) away from the plants. If your basil plant grows taller, move the lights up, or the plants down.


Basil starts from the seed (germinates well under Nurser 3), so you can experiment with different types of basil. They will germinate in about 7 days. You could place the seeds in a seedling tray filled with potted soil, or in a sponge cube or rock-wool. Alternatively, you could start from a clone. To start from a clone, select a stem that does not have a seed stalk, the stem should be at least 7 to 10cm (3 to 4 inches) tall, remove the bottom leaves, only leaving some on top and place the basil plant in the water. Within 2 weeks the clone will develop new roots and you can transfer this clone into a pot.


Basil is one of the most popular herbs. You can make great pesto with it, with cheeses, fresh garlic, olive oil and salt. Puree the mixture in a blender and stir it directly in the freshly cooked pasta.

Leafy greens

Leafy greens such as lettuce is a popular crop for hydroponic growers. It grows really fast and requires a lot less water than growing in soil. Some popular lettuces are: Red and green romaines, oak leaves, green leafs.

Lettuce key info

Growth cycle: 42-56 days

Seed: day 0

Germination: 2-14 days

Transplant: 3-4 weeks

Harvest: 5-6 weeks

Light requirements: 150 to 250 μmol/m2/s (vegetative phase)

Light requirements: 80 μmol/m2/s (seedling phase)

Photoperiod: 10 to 18 hours per day

Temperature: 7°C to 21°C (45°F to 70°F)

Store Temperature: 0°C to 1°C (32°F to 35°F), keep temperature consistent

Relative Humidity: 50-70%

Closest distance from fixture: 7-33cm (3-13”)

Hydroponic water EC/PPM: 0.8 to 1.2

Hydroponic water pH range: 5.6 to 6.2

How to grow leafy greens

Lettuce likes cold. High temperature makes lettuce bolt and bitter. Avoid high temperatures. When you harvest lettuces make sure too cool it down quickly (but not freezing) so it gets into lower respiration rate. Lettuce can grow well with strawberries, which also likes low EC


For seedlings you need about 80 μmol/m2/s with Nurser 3 and for vegetative growth you need about 50 to 250 μmol/m2/s with Nurser 3. You could run the lights for 10 to 18 hours. Some people run 24 hours per day, but it is better to let the lettuce grow during the day and rest at night.