Growing Zucchini & Squash Hydroponically: A Complete Tower Garden Guide
Zucchini and squash are some of the most satisfying crops to grow hydroponically. They grow quickly, produce huge leaves and can go from a tiny seedling to a plant taking over a large section of your Tower Garden before you know it.
They're also crops where a little planning makes a big difference. Squash plants need plenty of light and room, and pollination becomes especially important once they start flowering. If you've ever watched a tiny zucchini begin to grow and then turn yellow, shrivel or rot, there's a good chance pollination was the problem.
🌱 The realistic answer: Zucchini and summer squash grow extremely well in a Tower Garden, but they're big plants. Don't let the size of the seedling fool you. Give them room from the beginning and learn how to recognize male and female flowers — those two things will make growing squash much easier.
Zucchini & Squash Growing Guide
Choosing Squash Varieties for Hydroponics
"Squash" covers a huge range of plants. Zucchini, yellow squash, pattypan squash and large vining winter squash don't all behave the same way in a Tower Garden.
Zucchini
Zucchini is one of the easiest types of squash to grow hydroponically. Most varieties grow as large bush-type plants rather than long vines, but those bushes can still become very large.
Yellow & Summer Squash
Yellow squash and other summer squash grow similarly to zucchini. They're fast-growing, productive plants that need plenty of space and regular harvesting once production begins.
Vining & Winter Squash
Larger vining squash can also be grown hydroponically, but they require much more room. You'll need somewhere for the vines to grow and a plan to support heavier developing fruit.
For most Tower Garden growers, zucchini and bush-type summer squash are the easiest place to start. They still need space, but managing them is much simpler than trying to accommodate a large winter squash vine.
Starting Zucchini and Squash From Seed
Plant 1 zucchini or squash seed per rockwool cube. Squash seeds are large and generally develop into vigorous seedlings quickly once they germinate.
Keep the rockwool evenly moist while the seed germinates. Once the seedling emerges, give it plenty of light so it develops strong growth.
Squash seedlings grow fast. You don't need to wait for a large plant before moving it into the Tower — once the seedling is established and has begun growing well, it can continue developing in its final Tower location.
For more information on starting crops in rockwool, see our How Many Seeds Should I Plant? article and Seeds & Seedlings Guide.
Where Should Squash Go in a Tower Garden?
Squash is one crop where you really need to think about the mature plant rather than the seedling you're holding in your hand.
Zucchini and summer squash produce very large leaves that can easily shade smaller plants. Place them where they'll have room to spread without covering everything around them.
Lower openings can work particularly well because the plant can grow outward without blocking as much light from crops below it. You'll also want easy access to the flowers for pollination and to the developing squash for harvesting.
Don't overcrowd your Tower. You can grow different types of crops together and they don't need separate nutrients, but physical space still matters. A Tower packed with young zucchini, cucumbers, tomatoes and eggplants can become a jungle once those plants mature.
How Much Light Does Zucchini Need?
Zucchini and squash are fruiting crops and need plenty of light to grow and produce well.
Outdoors, position your Tower where the plants receive plenty of direct sunlight. Indoors, provide approximately 14–16 hours of grow light each day followed by complete darkness overnight.
With Tower Garden grow lights, keep the lights approximately 6–8 inches from the tops of the plants. This can become challenging with a mature squash plant because the leaves spread so widely, which is one reason variety and placement are especially important indoors.
See our Tower Garden Light Guide for more information about indoor and outdoor lighting.
What Temperature Does Squash Like?
Zucchini and squash are warm-season crops. They grow best once conditions have warmed and can struggle when temperatures are too cool.
Here in Florida, cold is often less of a concern than excessive summer heat. During very hot weather, pay extra attention to the Tower's reservoir. Large squash plants can use a surprising amount of water.
Heat can also increase plant stress and contribute to problems such as wilting during the hottest part of the day. Check the reservoir before assuming a drooping plant needs some other treatment.
Water and Nutrients for Zucchini & Squash
Once established, zucchini and squash are large, fast-growing plants. Consistent water and nutrients become increasingly important as they begin flowering and producing fruit.
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.
During very hot weather, we may reduce nutrient strength further, sometimes to half or even quarter strength depending on conditions.
Keep the pH approximately 5.5–6.5 and monitor the reservoir frequently as the plants get larger.
You don't need separate nutrients for zucchini or squash. They can grow in the same Tower and nutrient solution as your other crops.
For more detail, see our Tower Garden Nutrients Guide and Tower Garden Water Guide.
How to Pollinate Zucchini and Squash
This is one of the most important things to understand when growing zucchini and squash.
Squash plants produce separate male and female flowers on the same plant. Pollen has to move from a male flower to a female flower before the squash can develop properly.
How to Tell Male and Female Squash Flowers Apart
Male flowers grow on a relatively thin stem. When you look inside the flower, you'll see the pollen-producing structure in the center.
Female flowers are easy to recognize because there is a tiny immature squash directly behind the flower. It looks like a miniature zucchini or yellow squash before the flower even opens.
That tiny squash isn't proof that pollination worked. It's the ovary of the female flower. If the flower isn't successfully pollinated, that little squash may stop growing, turn yellow or brown, shrivel and eventually fall off.
Why Do I Have Lots of Flowers but No Zucchini?
Don't panic if your plant produces male flowers first. This is common, particularly when the plant is young. Male flowers often appear before female flowers begin opening.
Once you have both male and female flowers open at the same time, bees and other pollinators may handle the job outdoors. Indoors, you'll need to hand pollinate. We often hand pollinate outdoors too when we want to make sure a female flower gets pollinated.
How to Hand Pollinate Squash
You can use a small paintbrush or cotton swab to transfer pollen from inside a male flower onto the center of a female flower.
You can also remove a male flower, peel back the petals and gently touch the pollen-covered center directly to the female flower.
For photos and more detailed instructions, see our guide to hand pollinating zucchini and other fruiting crops.
Does Zucchini Need Pruning or Support?
Bush-type zucchini doesn't need a trellis in the same way a cucumber vine does, but the plant can become large and heavy. Keep an eye on how it is growing around the Tower and make sure it isn't smothering neighboring plants.
Remove badly damaged, diseased or dying leaves when needed. Older lower leaves can also be removed if they're crowding the Tower or restricting airflow.
Avoid removing large numbers of healthy leaves just to make the plant smaller. Those leaves are producing the energy the plant needs to grow squash.
Vining squash is different. Long vines will need to be directed or supported, and heavier fruit may need a sling or other support so its weight isn't hanging from the vine.
Can You Grow Zucchini Indoors?
Yes — but zucchini is one of those crops where "can I?" and "is it practical?" aren't quite the same question.
A mature zucchini plant is big. If you're growing indoors, make sure you have enough room around the Tower for its leaves to spread and enough grow-light coverage for the entire plant.
You'll also need to hand pollinate the female flowers because there aren't bees flying around your living room.
If indoor space is limited, consider how many large fruiting crops you're growing at once. A Tower with one zucchini plant alongside greens, herbs and other compact crops is much easier to manage than one filled entirely with large fruiting plants.
See our guide to the best compact plants for indoor Tower Gardens when planning an indoor setup.
Common Zucchini and Squash Problems
My tiny zucchini starts growing and then dies
Poor pollination is one of the first things to check. The tiny squash behind a female flower can begin to develop but then stop, discolor and shrivel if pollination wasn't successful.
My squash has lots of flowers but no fruit
First determine whether you're seeing male flowers, female flowers or both. Young squash plants often produce male flowers before female flowers appear. Once both are opening, make sure the female flowers are being pollinated.
The plant wilts during the day
Large squash leaves lose a lot of water, particularly in hot weather. Check the Tower's reservoir and root system. Temporary wilting during extreme afternoon heat can happen even when water is available, but persistent wilting needs investigation.
Leaves are turning yellow
Check pH, nutrient strength, reservoir level, roots, temperature and the age and location of the affected leaves before assuming the plant simply needs more nutrients.
The fruit is misshapen
Incomplete pollination can contribute to poorly developed or misshapen squash. Plant stress and inconsistent growing conditions can also affect fruit development.
Common Squash Pests and Diseases
Powdery Mildew
Powdery mildew is one of the most common problems you'll encounter with zucchini and squash. It appears as white, powdery patches across the leaves and can spread rapidly when conditions favor it.
Good airflow helps, which is another reason not to overcrowd large squash plants. Some varieties also have better powdery-mildew resistance than others.
Aphids and Whiteflies
Check the undersides of leaves regularly. Aphids and whiteflies can build up quickly on squash, particularly when dense foliage makes infestations easy to miss.
Squash Bugs
Outdoor squash can also attract squash bugs. Inspect the undersides of leaves and stems regularly so problems are caught before populations become large.
Spider Mites
Hot, dry conditions can encourage spider mites. Fine stippling or discoloration on the leaves may be an early sign, with fine webbing appearing as infestations become heavier.
For more help identifying and treating problems, visit our Tower Garden Pests & Diseases Guide.
When Should You Harvest Zucchini and Summer Squash?
Bigger isn't necessarily better.
Zucchini and summer squash are generally at their best when harvested while they're still relatively young and tender. If you leave them on the plant too long, they can become oversized, tougher and seedier.
Once the plants begin producing, check them frequently. Squash can grow remarkably quickly and a fruit that looked small yesterday may suddenly be ready to harvest.
Use clean scissors or pruning shears to cut the fruit from the plant rather than pulling or twisting it from the stem.
🥒 Keep harvesting. Regularly picking zucchini and summer squash while the fruit is young encourages you to actually use the harvest — and prevents you from discovering a baseball-bat-sized zucchini hiding under a leaf three days later.
Is Zucchini a Good Crop for a Tower Garden?
Absolutely. Zucchini and summer squash grow quickly, they're productive, and watching the flowers turn into squash is one of the more rewarding parts of growing fruiting crops.
They're not small plants, though. Give them enough space, plenty of light and consistent water and nutrients. Learn to recognize male and female flowers, help with pollination when necessary, and keep an eye out for powdery mildew and pests.
Do those things and zucchini can be a fantastic addition to a mixed Tower Garden.
Ready to Grow Zucchini or Squash?
Living Towers offers zucchini and squash seeds and seedlings ready for hydroponic, aeroponic and traditional growing.
Our seedlings can be grown in Tower Garden, other hydroponic systems, Lettuce Grow, containers or soil.
