Growing Broccoli Rabe Hydroponically: A Tower Garden Growing Guide

Broccoli Rabe Quick Facts

Broccoli rabe is a relatively quick crop, making it a good choice when you don't want to wait months for a harvest. Under good growing conditions, plants can be ready to harvest in approximately 40–50 days.

Starting Broccoli Rabe from Seed

Broccoli rabe is easy to start from seed. We recommend planting 1–2 seeds per rockwool cube. You don't need to fill the cube with seeds to get a healthy plant.

Under good conditions, the seeds generally germinate in approximately 5–7 days.

Keep the rockwool evenly moist during germination without leaving it sitting in standing water. Once the seedlings are established and roots begin growing from the cube, they can be moved into the Tower Garden or another hydroponic system.

If both seeds develop into strong seedlings, thin them so the remaining plant has enough room to mature.

Not sure how many seeds to use for your other crops? See our guide to how many seeds to plant.

Where Should Broccoli Rabe Go in a Tower Garden?

Broccoli rabe doesn't need the extensive space or support required by large fruiting plants such as tomatoes and cucumbers, so it's relatively easy to place in a Tower Garden.

Give the plant enough room for its leaves to spread and make sure larger neighboring plants won't shade it as the tower fills in.

Because broccoli rabe doesn't require a cage, trellis or hand pollination, it's also a straightforward crop for indoor Tower Gardens.

Light and Temperature for Broccoli Rabe

Growing Broccoli Rabe Outdoors

Broccoli rabe generally performs best in good light and moderate temperatures. It's commonly treated as a cool-season crop, but our experience has shown that it can be more adaptable than that description suggests.

We've successfully grown broccoli rabe at Living Towers in the Florida Keys in temperatures above 85°F. Hotter conditions can increase water use and plant stress, so keep an eye on the reservoir and the overall health of the plant when temperatures climb.

Growers in very hot climates may find that broccoli rabe performs differently depending on the season, but that doesn't mean it can only be grown during cold weather.

Growing Broccoli Rabe Indoors

When growing broccoli rabe indoors under LED grow lights, provide approximately 14–16 hours of light each day, followed by complete darkness overnight.

We generally start Tower Garden LED lights approximately 6–8 inches above the tops of the plants and adjust them as the plants grow.

If plants begin stretching or producing weak growth, check the amount of light they're receiving as well as the distance between the lights and the plant canopy.

For more information about both indoor and outdoor lighting, visit our Tower Garden Light Guide.

Water, pH and Nutrients

Broccoli rabe can grow alongside other crops in a Tower Garden and doesn't require its own special nutrient formula.

For established plants, our standard Tower Garden nutrient rate is 20 mL Mineral Blend A and 20 mL Mineral Blend B per gallon of water.

For young seedlings, we generally start at approximately half strength: 10 mL of A and 10 mL of B per gallon.

Keep the nutrient solution at approximately pH 5.5–6.5.

During hot weather, plants may use water considerably faster. Check the reservoir regularly and adjust your routine for the growing conditions rather than relying on the same schedule year-round.

For more information, visit our Tower Garden Nutrients Guide and Tower Garden Water Guide.

Common Broccoli Rabe Problems

Broccoli rabe is relatively easy to grow, but there are a few things worth watching as your plants develop.

Yellowing Leaves

If multiple leaves begin yellowing or the new growth doesn't look healthy, check nutrient strength, pH, water quality, light and root health. One older leaf declining isn't necessarily a sign that the entire plant has a problem.

Wilting or Heat Stress

Even though we've successfully grown broccoli rabe above 85°F, plants can still experience heat stress. Make sure the reservoir has enough water and that the pump and irrigation system are operating correctly.

Weak or Stretched Growth Indoors

Long, weak growth can be a sign that the plant isn't receiving enough light. Check both the lighting schedule and the distance between the plant and the LEDs.

Pests

Broccoli rabe is a brassica, so keep an eye on the leaves for chewing damage and other signs of pests. Check both the tops and undersides of the leaves regularly so you can catch problems early.

If you notice insects, leaf damage or another plant problem, use our Pests & Diseases Guide to help identify what's happening and what to do next.

When and How to Harvest Broccoli Rabe

Broccoli rabe grows quickly. Depending on the variety and growing conditions, you can generally expect to begin harvesting around 40–50 days after planting.

The leaves, stems and small broccoli-like flower buds are all edible. For the best eating quality, harvest while the stems are tender and the flower buds are still closed rather than waiting for the plant to produce a mass of open flowers.

You can cut usable stems and leaves as the plant develops rather than waiting for one enormous harvest.

How to Enjoy Broccoli Rabe

Broccoli rabe has a distinctive, slightly bitter flavor that works particularly well with bold ingredients. The stems, leaves and flower buds can all be eaten, so very little of the harvested plant needs to go to waste.

One of the simplest ways to prepare it is to sauté it with olive oil and garlic. It also works well in pasta dishes, alongside beans, in soups or as a cooked green served with a main meal.

If you find the flavor stronger than you prefer, briefly blanching the broccoli rabe before sautéing can soften some of its bitterness.

Why Grow Broccoli Rabe?

Beyond being quick and relatively easy to grow, broccoli rabe gives you a nutrient-dense leafy green that can go from your Tower Garden to the kitchen in a matter of weeks.

It's also a useful crop for growers who want something different from the usual lettuce and herbs while still avoiding the long wait and additional support required by many fruiting crops.

Is Broccoli Rabe a Good Hydroponic Crop?

Yes. Its relatively fast growth, compact habit and lack of pollination or support requirements make broccoli rabe well suited to Tower Garden and other hydroponic or aeroponic systems.

It's particularly useful if you want to diversify beyond lettuce and herbs without giving up a large amount of growing space to a long-season crop.

And despite its reputation as a cool-season vegetable, our experience growing it in the Florida Keys shows that growers in warmer climates shouldn't automatically rule it out.

Looking for more ideas? Visit our Hydroponic Crop Library to explore growing guides for leafy greens, herbs, fruiting crops and other vegetables.

Continue Learning