Growing Cabbage Hydroponically: A Complete Tower Garden Guide
Cabbage grows very well hydroponically, but it's another crop where patience — and planning for the mature size of the plant — matters. A tiny cabbage seedling eventually develops a large spread of outer leaves before forming the tight head you're waiting to harvest.
Like broccoli and cauliflower, cabbage is a cool-weather crop. It can take almost three months for a head to form, so it's worth considering both the season and how you want to use the available space in your Tower.
Cabbage Growing Guide
Cabbage Varieties for Hydroponic Growing
There are many types of cabbage, and choosing a variety suited to your growing conditions and available space is important when growing hydroponically.
Living Towers currently offers two cabbage varieties as hydroponic-ready seedlings: Capture and Primero.
Capture Cabbage
Capture is one of the cabbage varieties we grow and offer as a seedling. Like other heading cabbages, give it enough room for the outer leaves to spread while the head develops in the center.
Primero Cabbage
Primero is another option we offer as a seedling. It has the same basic needs as other heading cabbages: plenty of light, cooler growing conditions and enough space to mature.
Starting Cabbage From Seed
When starting cabbage from seed, plant 1 seed per rockwool cube.
Keep the rockwool evenly moist during germination without leaving the cube sitting in excess water. Once the seedling emerges, provide plenty of light so it develops sturdy, compact growth.
As with broccoli and cauliflower, don't use the size of the young seedling to decide how closely to pack your Tower. Cabbage becomes a substantially larger plant as it matures.
Living Towers does not currently sell cabbage seeds, but we offer Capture and Primero cabbage seedlings for growers who want to start with an established hydroponic-ready plant.
For more information about starting plants in rockwool, see our How Many Seeds Should I Plant? article and Seeds & Seedlings Guide.
Where Should Cabbage Go in a Tower Garden?
Cabbage develops a wide spread of outer leaves, so give it enough room to mature without crowding neighboring plants.
Think about what will be growing immediately above, below and beside the cabbage. Smaller crops can eventually become shaded if a mature cabbage plant spreads over them.
You don't need to grow an entire Tower of cabbage. Cabbage can be mixed with lettuce, herbs, kale and other cool-season crops as long as you account for the different mature plant sizes.
🌱 Plan for the mature plant. The cabbage seedling you plant today is small. The plant you're making room for is the one you'll have almost three months from now.
How Much Light Does Cabbage Need?
Cabbage needs plenty of light to produce strong growth and eventually develop a good head.
Outdoors, place your Tower where the plants receive plenty of direct sunlight during the cooler growing season.
Indoors, provide approximately 14–16 hours of grow light per day, followed by complete darkness overnight.
With Tower Garden grow lights, keep the lights approximately 6–8 inches from the tops of the plants. As the cabbage grows, check the distance regularly and make sure the expanding leaves aren't blocking too much light from neighboring crops.
See our Tower Garden Light Guide for more information.
What Temperature Does Cabbage Like?
Cabbage is a cool-weather crop, which makes the time of year you grow it particularly important.
In warmer climates, cabbage is better suited to the cooler growing season rather than the hottest part of the year.
This is especially important because cabbage isn't a quick crop. If you're waiting almost three months for a head to develop, you'll want to start early enough that the plant isn't reaching that stage just as conditions become too hot.
🌡️ Work backward from the weather. Don't only ask whether it's cool enough to plant cabbage today. Think about what the weather is likely to be several weeks from now, when the plant is much larger and beginning to form its head.
Water and Nutrients for Hydroponic Cabbage
Cabbage doesn't require its own special nutrient formula and can grow alongside other crops in a mixed Tower Garden.
For an established Tower Garden, our standard Mineral Blend rate is 20 mL of Mineral Blend A and 20 mL of Mineral Blend B per gallon of water.
For young seedlings, use approximately half strength — 10 mL of A and 10 mL of B per gallon.
Keep the Tower's pH approximately 5.5–6.5 and check the reservoir regularly. Larger, mature plants can change how quickly the Tower uses water compared with a Tower filled with young seedlings.
For more detail, see our Tower Garden Nutrients Guide and Tower Garden Water Guide.
How Long Does It Take Cabbage to Form a Head?
This is where cabbage requires patience. It can take almost three months for a cabbage head to form.
For much of that time, the plant is producing its large outer leaves. Eventually the newer leaves in the center begin growing more tightly together and the familiar cabbage head starts to develop.
Don't assume something is wrong simply because you have a large, healthy cabbage plant without a tight head early in the growing cycle.
🥬 Give it time. Heading crops are very different from lettuce or kale that you can begin harvesting relatively early. With cabbage, much of the reward comes at the end of a longer growing cycle.
Can You Grow Cabbage Indoors Hydroponically?
Yes. Cabbage can be grown indoors hydroponically as long as you can provide enough light and physical space for the mature plant.
The biggest consideration isn't whether cabbage can grow indoors — it's whether you want to dedicate that much indoor growing space to a crop that may take almost three months to form a head.
Indoor growing does have an advantage in warmer climates because you have more control over temperature. A cool indoor growing space can make cabbage possible when outdoor temperatures aren't ideal.
If indoor space is limited and maximizing repeated harvests is the priority, compact herbs and leafy greens may provide more food from the same space.
See our guide to the best compact plants for indoor Tower Gardens for more ideas.
Common Problems When Growing Cabbage Hydroponically
My cabbage is huge but isn't forming a head
Consider the age of the plant first. Cabbage can take almost three months to form a head. If the plant is healthy and still relatively young, it may simply need more time.
Also consider temperature, light and overall plant health if a mature plant isn't heading as expected.
The outer leaves are shading everything else
This is usually a spacing issue rather than a problem with the cabbage itself. Cabbage naturally develops a substantial spread of outer foliage. Plan neighboring crops around the mature size of the plant.
The cabbage is struggling as the weather gets warmer
Cabbage prefers cool conditions. If you're growing outdoors, timing the crop so most of its development happens during the cooler season can make a significant difference.
The leaves are yellowing
Check the overall plant rather than automatically adding more nutrients. Look at pH, nutrient strength, roots, water conditions, light and temperature. A few declining older outer leaves are also different from widespread yellowing throughout the plant.
Common Cabbage Pests and Diseases
Like broccoli and cauliflower, cabbage belongs to the brassica family and can attract several common leaf-feeding pests.
Caterpillars
Chewed leaves and irregular holes are often the first signs you'll notice. Check both sides of the leaves regularly and inspect the inner growth as the head begins developing.
Aphids
Aphids can cluster on tender growth and hide between leaves. Catching them before a population becomes established makes them much easier to manage.
Whiteflies
Whiteflies commonly hide on the undersides of leaves. Adults may fly up when the plant is disturbed.
Leaf Spots and Disease
Good airflow becomes increasingly important as cabbage leaves get larger and plants begin crowding one another. Identify the cause of spotting or discoloration before deciding how to treat it.
See our Tower Garden Pests & Diseases Guide for help identifying and managing common problems.
When Should You Harvest Cabbage?
Cabbage is ready to harvest once the central head has developed and feels firm and compact.
Head size will vary, so don't rely on diameter alone. Watch the plant's development and check the firmness of the head as it approaches maturity.
Use a clean knife or pruners to cut the cabbage head from the plant.
🥬 This is the payoff. Unlike kale or herbs, where you're harvesting throughout the growing cycle, cabbage asks you to wait. That makes finally cutting a full head after watching it develop for weeks particularly satisfying.
Is Cabbage Worth Growing in a Tower Garden?
It depends on what you want from your Tower.
If your priority is harvesting as much food as possible from every planting port, cabbage has competition. It takes almost three months to form a head, becomes a fairly large plant and gives you one primary harvest.
Kale, lettuce and many herbs can provide repeated harvests during the same period.
But that doesn't mean cabbage doesn't belong in a Tower. Growing a full cabbage head without soil is fun, and you don't need to dedicate the entire Tower to it.
A mixed Tower lets you grow one or two cabbage plants while filling the remaining ports with faster or continuously harvested crops.
🌱 Mix your harvests. A Tower doesn't need to contain 20 plants that all mature at the same time. Combining longer-term crops such as cabbage with lettuce, herbs and greens can give you something to harvest while you wait for the cabbage heads to develop.
Ready to Grow Cabbage?
Living Towers offers Capture and Primero cabbage seedlings, ready to plant into your Tower or other growing system.
Our seedlings can be grown in Tower Garden, other hydroponic systems, Lettuce Grow, containers or soil.
