Container vegetable gardening — what to grow in 10L pots

Container vegetable gardening — what to grow in 10L pots

You don't need a garden to grow food. A sunny balcony, patio, or fire escape can feed a household more than most people imagine — tomatoes, peppers, salad greens, herbs, strawberries, even potatoes all thrive in containers. The catch: containers are less forgiving than ground beds. Pots dry out fast, nutrients leach quickly with daily watering, and root volume limits the plant's potential. This guide covers the pot size minimums for each major crop (the single biggest determinant of success), the soilless potting mix that university Extension trials consistently recommend, the self-watering setups that double your time between waterings, and the 12 vegetables that consistently produce well in pots. The container itself matters too — terracotta, plastic, fabric and self-watering pots each behave differently, which we break down in the types of pots for plants guide.

Plan a container garden in Growli: Add your pots and crops to the Growli app and we'll build a watering and feeding schedule for each, with reminders before heatwaves and frost nights.

Why containers — and why containers fail

The advantages: instant garden anywhere with sun, no soil-prep, full control over soil quality, easy to relocate for sun or frost protection, accessible for limited-mobility gardeners.

The risks (and how to avoid them):

1. Pots dry out fast. Container soil dries 2-3x faster than ground beds. Daily watering in summer is the norm, not an option.
2. Nutrients leach with watering. You'll need to feed more often than ground gardens.
3. Restricted root volume limits plant size. A tomato in a 20-litre pot won't match a tomato in open soil. Pick container-bred cultivars and use bigger pots than you think.
4. Heat stress on roots. Dark pots in full sun cook the roots. Use light-coloured pots or double-pot for insulation.

Pot size minimums by crop (University Extension data)

The single most important table in this guide. These minimums come from US University Extension trials (Maryland, Wisconsin, Texas A&M, Illinois, Oregon State):

Use our pot size calculator to convert from US gallons or litres and check your specific cultivar.

Soilless potting mix vs garden soil — settled science

The debate is settled. University Extension consensus: use bagged soilless potting mix for containers, not garden soil.

The reasons:

• Garden soil compacts when placed in a container, leading to poor drainage, poor aeration, and root suffocation.
• Garden soil carries weed seeds, insects, and disease organisms — a problem in the closed container environment.
• Soilless mix is sterile and structured for the demands of container growing — sphagnum peat moss, perlite, vermiculite, and coconut coir give drainage and aeration that compacted soil can't match.

The cheap alternative: amend garden soil to a 1 part soil / 1 part peat / 1 part perlite blend. It works but is more variable than bagged mix.

For full mix selection, see our potting mix primer.

Self-watering containers — what they are and when to buy them

Self-watering containers have a water reservoir below the soil that wicks moisture up via capillary action. Benefits:

• 2-4 days between waterings instead of daily.
• More even moisture — fewer wide swings that cause blossom end rot.
• Lower water waste — closed system retains water that would drain through ordinary pots.

The best-tested commercial option is the Earthbox-style sub-irrigated planter. DIY versions work fine — two stacked buckets, a wick of fabric, a fill tube on the side.

Self-watering is most useful for high-water crops in hot summers: tomatoes, peppers, cucumbers. Less critical for herbs and lettuce in cooler weather. Take the water-reservoir idea one step further and you arrive at soilless growing — our guide to hydroponic vegetables covers the indoor, year-round version of the same principle.

Light — the hard limit

Fruiting crops (tomatoes, peppers, cucumbers, zucchini, strawberries) need 6+ hours of direct sun. No exceptions. A balcony with 4 hours of sun will grow herbs and salad greens but won't ripen tomatoes.

Leafy crops (lettuce, spinach, kale, chard) tolerate 4-6 hours and actually benefit from afternoon shade in summer heat.

Root crops (carrots, radishes) need 4-6 hours.

If you have north-facing or shaded conditions, focus on herbs and salads. Don't waste pot space on tomatoes that won't ripen.

Watering containers — the routine

The single biggest difference from ground gardening. The rules:

• Check daily in summer. Lift a small pot to feel its weight; sink a finger 2 inches into a larger one. Water if dry.
• Water until water runs out the bottom. Half-watering wets only the top, leaves the lower roots dry, and accumulates salt at the surface.
• Morning watering is best — leaves dry before night, reducing fungal disease.
• Mulch surfaces of large pots with straw, coir, or bark chips to slow evaporation. See mulch.
• Saucer water is fine for an hour but tip it out — standing water causes root rot.

Use our water calculator for the wider watering plan.

Feeding containers

Containers leach nutrients faster than ground beds. The schedule:

1. At planting: mix slow-release fertiliser into the potting mix (most bagged mixes include 2-3 months of feed; check the label).
2. From flowering: liquid feed weekly at half-strength. Tomato fertiliser (high potassium) works for fruiting crops; balanced for leafy.
3. In mid-summer: if leaves yellow despite watering, top up with slow-release pellets.

Never feed dry plants — water first, then feed once soil is moist.

The 12 best vegetables for containers — and what to skip

The 12 that thrive in pots

1. Tomatoes (dwarf or bush) — Patio, Tiny Tim, Bush Early Girl. See how to grow tomatoes.
2. Peppers — bell, jalapeño, habanero. All do well in 10L pots. See how to grow peppers.
3. Strawberries — strawberry pots and hanging baskets specifically designed for them. See how to grow strawberries.
4. Lettuce — succession-sow in window boxes for steady salad. See how to grow lettuce.
5. Herbs — basil, parsley, chives, mint, oregano, thyme. The highest-value container crop. See how to grow basil.
6. Spinach and kale — leafy crops with shallow roots.
7. Cucumbers (bush) — Spacemaster 80 or Bush Champion. See how to grow cucumbers.
8. Zucchini (bush, one plant per 30L pot) — Defender F1, Eight Ball. See how to grow zucchini.
9. Radishes — fast container crop, 30 days seed to plate.
10. Carrots (Paris Market or short types) — see how to grow carrots.
11. Bush beans — 3-4 plants per 10L pot, productive for weeks.
12. Potatoes — in 40L potato bags or buckets, easy harvest by tipping out.

What to skip in containers

• Sweet corn — needs blocks of plants for pollination, too tall for most pots.
• Pumpkins and winter squash — too sprawly and demanding.
• Asparagus — perennial that needs years to establish, ground only.
• Brussels sprouts — root-bound easily, slow to mature.
• Watermelon — possible in 80L+ pots but rarely worth the space.

Companion planting in containers

Even small pots can host two crops. Lettuce or radishes interplanted between slow-growing tomatoes or peppers maximise the space — they harvest before the bigger crop closes canopy. See our companion planting guide for the matrix.

Common container polycultures:

• Tomato + basil + parsley in a 30L pot (the classic "salsa pot").
• Pepper + nasturtium — nasturtium acts as aphid trap.
• Strawberry + chive — chive masks strawberry from aphids.

Overwintering and reusing potting mix

In cold zones, containers freeze faster than ground beds — bring small pots indoors or wrap large ones in fleece. Most annual crops are pulled at frost.

Reuse potting mix for 1-2 seasons, refreshing with fresh slow-release fertiliser and 30% new mix at the start of each year. After 2 seasons, dump the spent mix on the compost heap and start fresh — accumulated salts and depleted structure limit yields.

Related articles

• How to grow tomatoes — container-bred cultivars
• How to grow peppers — perfect 10L pot crop
• How to grow strawberries — strawberry pot setup
• How to grow lettuce — window box salads
• How to grow basil — 2L pot indoors or out
• How to grow cucumbers — bush cultivars for pots
• How to grow zucchini — bush types for 30L pots
• How to grow carrots — Paris Market in 4L pots
• How to start a vegetable garden — wider beginner roadmap
• Companion planting guide — polycultures in pots
• Pot size calculator — match container to crop
• Plant spacing calculator — multi-plant pots
• Water calculator — container watering plan
• Frost-date calculator — overwintering windows
• USDA zones lookup — for timing
• UK hardiness ratings — for southern vs northern UK timing

Reviewed and updated by the Growli editorial team. For questions, open Growli or email hello@getgrowli.app.