How to Grow Cucumbers in Containers on a Small Balcony

My first cucumber plant lived on a fire escape in a pot about the size of a coffee can. It gave me one cucumber. One. It was bitter, curved like a question mark, and I ate it standing at the railing anyway, because I’d grown it and that felt like enough.

Six seasons on a balcony have taught me what that pot got wrong. Cucumbers are thirsty, hungry, and tall. Give them a big enough pot, a trellis, and steady water, and a single plant will hand you more cucumbers than you can eat in a week. You don’t need a yard for any of it.

You’ll also want a trellis, a tomato cage, or a stretch of string running up the railing. I haven’t found a balcony trellis I’d point you toward yet, so I use a plain bamboo teepee and zip ties, which costs almost nothing.

Pick a cucumber that suits a pot

This is the choice that matters most. A full-size vining cucumber can run eight feet or more, which is a lot to ask of a balcony. Look for the words “bush,” “patio,” or “compact” on the seed packet.

Spacemaster stays short, around two feet, and does well in a container.

Patio Snacker is a vining type that you can train up a small trellis, with crisp little fruits that are good for snacking.

Bush Champion gives full-size slicers on a plant that stays tidy.

Boston Pickling is an old standby if you want pickles, and it stays reasonably well-behaved on a trellis.

If you like a thin-skinned slicer, like the long English type, look for a variety labeled “parthenocarpic.” That’s a long word that means the flowers set fruit without a bee’s help, which matters a lot on a high balcony where pollinators are scarce.

The pot is the whole game

One cucumber plant wants a container that holds at least five gallons. Ten is better for a vigorous vine. A five-gallon fabric grow bag works well because the fabric breathes and the roots stay healthy. The trade-off is that fabric dries out faster than plastic, so in July you’ll water every day, sometimes twice.

Whatever you choose, it needs drainage holes. Fill it with a good potting mix to within an inch of the rim. Garden soil from a bag in the hardware store, or dirt from anywhere else, turns to concrete in a pot and strangles the roots.

Put one plant per five-gallon pot. Two plants in a pot sounds like more cucumbers, and it nearly always means two stressed plants.

When to sow, and where

Cucumbers hate cold. Wait until nights stay above 50 degrees and the soil feels warm to your hand, usually a week or two after your last frost date. Your local extension office lists that date. You can sow seeds straight into the pot, about an inch deep, three or four seeds to start and then snip the weaker ones at the soil line, leaving the strongest.

If you’d like a head start, sow seeds in small cups indoors three or four weeks before you plan to move them out. Cucumber roots dislike being disturbed, so use a biodegradable pot or handle the seedling gently, and don’t let it sit in the cup too long. I wrote a whole walk-through on starting seeds indoors on a windowsill if you’ve never done it. When the plants are ready, harden them off for a week before they stay outside for good.

They want six to eight hours of sun. A south or west railing is ideal. A balcony with only four hours of sun can still grow a few cucumbers, but the harvest will be smaller, and I’d stick to a compact variety.

Water like you mean it

Uneven watering is what makes cucumbers bitter and oddly shaped. A pot that goes dry, then gets soaked, then goes dry again stresses the plant, and the cucumbers show it.

Aim for steady moisture, like a wrung-out sponge. Push a moisture meter down into the root zone before you water, because the top inch lies. I use a long-spout can and pour slowly at the base until water runs out of the bottom. Wet leaves invite powdery mildew, the white dust that shows up on cucumber leaves in late summer, so I keep the water on the soil and water in the morning.

A layer of mulch on top, like a thin handful of shredded leaves or straw, slows the drying. It’s a small thing and it helps.

Feeding a fast grower

A cucumber plant puts out a lot of growth in a short season, and a pot has a limited supply of food. I mix a scoop of Garden-Tone into the top few inches of the pot at planting, following the amount on the package, and add a little more about every four weeks through the summer. If you want more detail on feeding, I wrote about how to fertilize container vegetables.

Train it up

Give the vine something to climb from the start. When the plant has a few true leaves, which are the leaves that look like a real cucumber leaf, set your trellis or teepee in the pot and tuck the first tendrils against it. After that the plant mostly climbs on its own, and you guide a stray stem now and then.

Growing up saves space, keeps the fruit off the dirty ground, and lets air move through the leaves, which cuts down on mildew. Otto has views on cucumbers that hang low enough to reach. He has not eaten one yet, but I wouldn’t bet against him.

Picking and problems

Pick often. A slicing cucumber is at its best around six to eight inches, firm and dark green. A cucumber left on the vine to grow huge and yellow tells the plant its job is done, and production slows. Pick every other day in peak season and the plant keeps going.

Two problems come up most. If the plant flowers but the tiny fruits shrivel, the female flowers, which have a small cucumber at the base, may not be getting pollinated. You can play bee yourself. Dab a small brush into a male flower, the ones on a thin stem without a baby cucumber, and touch it to the center of a female one. If you’ve grown a parthenocarpic variety, you can skip this.

The other is the cucumber beetle, a small yellow-and-black striped bug that chews leaves. On a balcony there usually aren’t many. Pick them off by hand in the morning when they’re slow.

A small, crisp pleasure

There’s nothing like walking out to the railing and pulling a cucumber you grew yourself, still cool from the night. It takes a decent pot, steady water, and a little patience, and not a single square foot of yard.

I go deeper on choosing containers, feeding, and getting more out of a few pots than you’d think possible in my book, Small-Space Big Harvest.