Some of the easiest hydroponic crops to grow are lettuce and other leafy greens such as Swiss chard, kale, and arugula. They don’t take up much space and grow quite quickly. Rich in micronutrients and diverse in color and flavor, lettuce is perfect for sandwiches or salads.
New Information About Lettuce
First, we need to learn a bit more about the plant itself. Lettuce is a cool-season vegetable, meaning it grows best at temperatures between 45°F and 80°F—ideal for indoor cultivation. It usually grows in a rosette shape, a tight spiral similar to rose petals. Lettuce is harvested before it bolts or flowers, because during that time, the stem thickens and elongates. The best part about lettuce and leafy greens is that your crops will be ready in 20–30 days, allowing you to turn over multiple harvests throughout the year.
The following hydroponic techniques are recirculating systems that work by pumping water up around the roots and then draining it out to bring in fresh oxygen. Water-soluble fertilizers are dissolved in the reservoir to provide nutrients to the plants. In multi-step fertilizing schedules, each nutrient addition should be fully dissolved before adding the next. The pH and electrical conductivity of the nutrient solution should be checked regularly, at least 2–3 times per week, and adjusted if needed. For lettuce, choose a fertilizer that promotes vegetative growth.
Beginners
What You’ll Need
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Lettuce seeds — any variety
If you’re looking for an easy solution, nothing is simpler than the Mega Garden. This product comes with everything you need to clone, grow, fertilize, and finish your plants conveniently. Mega Garden is ideal for microgreens (lettuce and other leafy greens harvested when small) or full-size lettuce, as the pots can be arranged close together or spaced out.
When starting lettuce seeds in rockwool cubes, set a timer to water the tray 1–2 times a day and use only the overflow drain without the extension tube. This keeps the water level low and prevents drowning the seedlings. DO NOT separate the cubes. Just soak them until evenly moist. Add RapidStart rooting enhancer to the reservoir and place the cubes in the tray, 2–3 seeds per cube, hole facing up. Turn on the grow lights to provide 12–18 hours of light per day.
When the seedlings are about 1″–1.5″ tall (2.5–3.5 cm), fill the pots with clay pebbles and place one seedling in each pot so that the clay sits inside the pot at least 1 inch (2.5 cm) below the rim. Now you can add one or two extension tubes to the overflow drain to raise the maximum water level as desired. Discard the old nutrient solution and replace it with fresh water. Place the pots in the tray and set the pump to run 3–7 times per day as needed.
Intermediate
Stuff You’ll Need
- Lettuce seeds – any variety: Starter plugs/rockwool mini-cubes
- Propagation tray with dome: 36L Hydroton Pebbles, rinsed
- 4×4” Rockwool Blocks: Active Aqua Flow Grow System
This automatic watering system from Active Aqua features adjustable buckets to ensure precise flood levels and a 55-gallon reservoir for even nutrient mixing. The buckets can be arranged in various configurations to fit any grow space. Moisten the seeds until evenly damp but not waterlogged. Sow the seeds into the rockwool cubes, 2–3 seeds per cube, and keep the dome on to maintain humidity. Turn on the grow lights for 12–18 hours daily.
Remove weak sprouts. When seedlings reach about 1″–1.5″ tall (2.5–3.5 cm), fill pots with clay pebbles and place one seedling into each 4″ rockwool block. Set the block into the clay pebbles so that there is at least 1 inch (2.5 cm) between the block and the pot’s rim. Set the pump timer to water 3–7 times throughout the lighting cycle. A secondary pump should be set to return water to the reservoir as soon as it reaches its maximum height. Add fertilizer to the reservoir. As the lettuce grows larger, more watering cycles may be needed each day.
Don’t forget lighting. Our previous article will help you choose the right grow lights for your grow room. Explore more grow lights, accessories, and more on our page in here: LED Grow Lights.
“Lettuce” help you take care of your greens! Whether your philosophy is “Start small” or “Go big or go home,” our knowledgeable staff is always ready to help you choose the right hydroponic system. The only thing greener than your thumbs will be your salad—or perhaps your neighbors’ jealous faces! Do you have any questions or comments?
See more information about hydroponic growing systems available here: Hydroponics DIY: How and Why to Grow Indoors