Grow light guide for indoor farming - hydroponics

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.

Other crops


grow guide Berries indoor

Berries love light and require at least 120 micromol. However they grow very well under 175 to 240 micromol with 14hr on and 10h off. The lights can be installed at around 30 to 40cm distance. Note that strawberries like moderate temperatures such as 23 to 25 degree during the day and 18 to 20 at night. They humidity should be maximum 70%. To get a headstart use bare root stock, which enables you to harvest within 10 weeks. Make sure you clean the roots thoroughly. You can also use your own runners and start from the seeds, however a strawberry plant that is grown from a seed might need about 2 years before it can produce fruits. Many people favor everbearing variety, which means they can constantly get some harvest. 


Many people use grow lights to propagate seeds, so they can get a head-start in the garden greenhouse or vegetable garden. For most seedlings you will need light that supports growth and development, such as the Nurser 3, which is available for consumers as a grow light set. You can use 12hr on/ 12hr off per day.

When you're ready to try growing your own food, there are several options to begin with. You can purchase young plants from a local gardening shop or nursery or you can begin with seeds. Plant nurseries specialize in producing high-quality and strong young plants that promise to do well when they grow up. However many people enjoy growing from seeds and watching seeds germinate and develop. Other benefits include the cost-effectiveness of seeds, clean plant material and a very wide variety to choose from. 

You can germinate seeds in front of a window sill or in any spare space in your home. The temperature should be consistent and make sure the air is kept moist. Seedling trays often have a cover as well to maintain humidity. Do not place seeds directly in sunlight, but place them at a shallow height in the soil. Once they sprout bright light/sun exposure is important, lighting plays an important role in photosynthesis. However, for seedlings, it also plays an important role to develop the plant organs such as roots. Good root development will help you to get strong and vigorous plants. Move plants to your garden or greenhouse when temperature permits (i.e. no night frost). In terms of lighting intensity, we recommend 20 micromoles to 100 micromoles. In the northern hemisphere, light levels in the winter behind a window can be notoriously low. It means that you might get as little as 5 micromoles on a cloudy or rainy day. In addition, days are short and seedlings prefer a consistent duration of light of at least 10 hours. Besides the lack of intense light and sufficient duration, the winter light does not contain enough deep red light which is very important for plants. A grow light can help you to boost the light. Use the home grow light set from HortiPower. it is optimized in lighting intensity, spectrum, uniformity, and height, which helps you to get strong seedlings.  Read more in this blog.

Edible flowers

Edible flowers make indoor farming and indoor gardening fun. They will also increase the appeal of your dish or cocktail. They too love light and require a lot of special red light that can trigger the flowering hormones of the plant. The Nurser 3 has the right quality of light to help you trigger flowering in the plant.


Anthuriums are a popular plant nowadays. They request some light, but not too much. The Nurser 3 is a good light to cultivate Anthuriums and the Bloomer 2 as well.


Succulents prefer bright light. Their color looks more beautiful when they grow in a bright space. Use the Nurser 3 at 30cm distance. 

Small Fruiting Vegetables

Cherry Tomato or "balcony tomato" will grow well under grow lights. Tomato is a light-loving crop and they will love to grow under at least 3 or 4 Nurser 3, depending on the width of your growshelf, or 2 pcs of Bloomer 2 that is directed at their top leaf. 

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