Home › Small spaces

Container Vegetable Gardening for Beginners (Balcony, Patio, Grow Bags)

Right pot size per crop, grow bags vs planters, and a watering routine that survives July.

Updated 2026-09-11

Container size per crop

Bigger is always easier. A 10-gallon tomato needs water once a day in July; a 5-gallon one twice. Buy 10-gallon bags and grow fewer plants.

Varieties that were bred for pots

Full-size tomatoes, vining squash, melons and corn fail in containers. Look for the words patio, bush, dwarf or compact: Tiny Tim, Patio and Bush Early Girl tomatoes; Spacemaster or Patio Snacker cucumbers; any bush bean; Bush Delicata squash; Lunchbox or Jalapeño peppers; and loose-leaf lettuce rather than heads.

Grow bags vs pots vs vertical planters

Fabric grow bags are the cheapest per gallon, air-prune roots and fold flat in winter; they dry out faster. Plastic pots hold water longer. A vertical planter (GreenStalk style) puts 30 plants of greens, herbs and strawberries on 2 sq ft, the best answer for a small balcony. A self-watering bed (Vegepod) is the low-maintenance option for a patio.

Every container needs drainage holes; a pot without them drowns a plant in one rainy week. Set grow bags on a saucer or a tray of gravel if the balcony below is someone else's.

Soil

Never garden soil: it compacts. Use potting mix plus 20–30% compost. Add a slow-release organic fertilizer at planting and feed every 2–3 weeks from July.

How much you need: a 5-gallon container holds about 0.7 cu ft, a 10-gallon about 1.3 cu ft. A 2 cu ft bag of potting mix fills three 5-gallon bags. For ten containers, buy a 3 cu ft bale of potting mix and a 1 cu ft bag of compost and mix on a tarp. The bed-soil ratios in the raised bed soil guide are too heavy for pots; keep the topsoil out.

Feeding

Potting mix runs out of food in about six weeks, and every watering washes more out. Mix a slow-release organic granular fertilizer into the top few inches at planting, then from early July feed tomatoes, peppers and cucumbers every two weeks with a liquid fertilizer at label strength. Greens and herbs need half that. Yellowing lower leaves in midsummer are hunger, not disease.

Watering in summer

Containers need water when the top inch is dry, which is daily in July for a 5-gal tomato. Solutions in order of effort: saucers, mulch, a drip kit with a timer (the real fix), or self-watering containers.

A 5-gallon tomato in full sun drinks about a gallon a day in July, and a missed day shows up as blossom-end rot two weeks later. Water until it runs from the bottom, in the morning. Six or more containers is the point where a drip kit with a 1 gph emitter per pot saves the summer; it takes an hour to set up and runs off the balcony tap.

Sun and wind on balconies

6 hours of sun minimum; south or west facing is ideal. Wind dries pots and snaps tomatoes: stake everything and put the tallest pots on the wall side.

Weight matters: a 10-gallon container of wet mix weighs about 60 lb, a 5-gallon about 30 lb. Spread them along the wall rather than at the railing. In hot zones (8–10) black pots cook roots by August; use light-coloured or fabric containers and give tomatoes afternoon shade.

A first balcony that works

Two 10-gallon grow bags with a cherry tomato and a bush cucumber on the wall side, two 5-gallon bags of bush beans and a pepper, a 12 in bowl of loose-leaf lettuce, and a pot each of basil and parsley. About $60 of containers and mix.

End of season

Pull the plants, tip healthy mix into a bin and reuse it next year with a third fresh compost and a new dose of fertilizer. Throw out mix from any container that had blight or wilt. Fabric bags wash and fold flat; empty plastic pots so freezing water does not crack them.

Mistakes to skip

• A full-size tomato in a 3-gallon pot.
• Garden soil or "topsoil" in containers.
• Pots without drainage holes, or sitting in a saucer of water for days.
• Feeding nothing after June and blaming the weather for pale plants.
• Ten small pots instead of four big ones.

FAQ

How many tomato plants can I put in a 5-gallon bucket?

One. A cherry or patio type does well; a full-size slicer wants 10 gallons or more. Drill drainage holes and stake it from day one.

Can I reuse potting mix from last year?

Yes, if the plants were healthy. Remove the roots, mix in a third fresh compost and a slow-release fertilizer. Replace mix that grew a diseased plant.

How often should I water vegetables in containers?

When the top inch is dry: every day for tomatoes and cucumbers in July, every 2–3 days for herbs and greens in spring. Water until it runs out of the bottom.

Which vegetables are easiest to grow in containers?

Loose-leaf lettuce, bush beans, radishes, cherry tomatoes and herbs. All of them tolerate a missed watering and produce within 60 days.

Do grow bags need saucers?

Not for the plant, but for the floor. Water runs straight through fabric, so use a saucer or tray on a balcony or deck, and empty it after heavy rain.

What I'd buy first

Save this guide on Pinterest for planning season.