How to Grow Tomatoes in Pots UK — A Complete Guide

I've been growing tomatoes on balconies, patios, and allotment edges across the UK for over a decade, and honestly, they're still my favourite crop. There is nothing — and I mean nothing — that beats a sun-warmed cherry tomato straight off the vine. If you think you need a greenhouse or a big garden to grow them, think again. Pots, a bit of sun, and a weekly feed are all you need.

This guide walks you through everything: choosing the right variety, picking pots and compost, planting, feeding, watering, and dealing with the inevitable UK summer weather. Whether you're on a south-facing balcony in Bristol or a patio in Edinburgh, you can absolutely grow cracking tomatoes in containers.

Step 1: Choose the Right Tomato Variety

The single most important decision is picking a variety suited to pot growing. Tomatoes fall into two main categories:

Determinate (bush) types — These grow to a set height, produce all their fruit within a few weeks, and don't need much pruning. Brilliant for smaller pots (8–10 litres). Look for varieties like Tumbling Tom, Patio Princess, or Balcony.

Indeterminate (cordon) types — These keep growing taller all season and produce fruit continuously until the first frost. They need a taller support stake and a bigger pot (at least 10–15 litres). Classic choices include Gardener's Delight (the best cherry tomato, in my opinion), Sungold, and Moneymaker.

For UK growers, I'd recommend starting with Gardener's Delight if you want cherry tomatoes, or Crimson Crush if you want larger slicing tomatoes with good blight resistance — which matters in our damp summers.

Step 2: Pick the Right Pots and Compost

Tomato roots need space and good drainage. Here's what to look for:

• Pot size: Minimum 10 litres for bush varieties, 15–20 litres for cordon types. A fabric grow bag works surprisingly well and costs very little.
• Drainage: Essential. If your pot doesn't have holes in the bottom, drill some. Tomatoes hate sitting in waterlogged soil.
• Material: Terracotta, plastic, or fabric — all work. Terracotta dries out faster so needs more frequent watering, which can actually be a bonus in wet UK summers.

For compost, use a quality multi-purpose compost mixed with about 20% perlite for extra drainage. Some people swear by tomato-specific compost, and it does work, but honestly a good multipurpose with a handful of perlite is just as effective and cheaper. Avoid garden soil in pots — it compacts, drains poorly, and can harbour soil-borne diseases.

Step 3: When and How to Plant

From seed: Sow indoors on a sunny windowsill from late March to mid-April. Place seeds on top of damp compost, cover lightly with 5mm of compost, and keep at 18–21°C. Germination takes 7–10 days. Once seedlings have two true leaves, pot them on into 9cm pots.

From plug plants: If you missed the seed window, most garden centres sell young tomato plants from May onwards. This is the easiest option for beginners — you can skip straight to the potting-up stage.

Harden off: Whether you've grown from seed or bought plug plants, gradually acclimatise them to outdoor conditions over 7–10 days before planting out. This means bringing them outside during the day and bringing them back in at night, especially if there's any risk of frost.

Planting out: Wait until late May or early June in most of the UK — overnight temperatures need to be consistently above 10°C. Fill your pot with compost, make a hole, and plant the tomato so the stem is buried up to the first set of true leaves. Tomatoes are unusual in that they root along the buried stem, giving you a stronger plant.

Step 4: Support and Training

Bush varieties are fairly self-supporting, though a small tomato cage or support ring keeps them tidy and prevents stems snapping under the weight of fruit.

Cordon types need a sturdy cane — I use 1.8m bamboo canes and tie the main stem to it every 20cm or so with soft garden twine. You'll also need to pinch out the side shoots (axillary buds) that appear between the main stem and the leaf branches. Do this weekly — just snap them off with your fingers when they're small. This directs the plant's energy into fruit production rather than a jungle of leaves.

Step 5: Feed and Water Consistently

This is where most container tomato growers go wrong. Pots hold limited nutrients and dry out much faster than ground soil.

Watering: Check daily, especially in summer. Stick your finger an inch into the compost — if it's dry, water thoroughly until it runs out of the drainage holes. Morning watering is ideal. In heatwaves, you may need to water twice a day. Inconsistent watering leads to blossom end rot (those horrible brown patches on the bottom of the fruit) and fruit splitting.

Feeding: Once the first flowers appear, switch from plain water to a tomato liquid feed — something high in potassium (K). Feed every 7–10 days, or every watering if you're using a dilute dose. I've tried most of the feeds on the market and find Westland, Chempak, and Tomorite all do a solid job. Tomorite is the classic and it's widely available.

Top dressing: Around July, when the plant is in full production, add a handful of slow-release fertiliser granules to the top of each pot. This provides a steady nutrient supply between liquid feeds.

Step 6: Deal with UK Weather

Let's be honest — British summers are unpredictable. Here's how I manage the common issues:

Blcool nights and lack of sun: Move pots against a south-facing wall for extra warmth. Dark-coloured pots absorb more heat, which helps.

Heavy rain: Bring container tomatoes under cover during prolonged rain if possible, or at least ensure excellent drainage. Wet foliage invites fungal diseases.

Blight: Late summer blight is the biggest threat in the UK. Look for dark brown patches on leaves and stems. Remove affected parts immediately. Growing blight-resistant varieties like Crimson Crush or La Diva is your best insurance policy.

Greenhouse advantage: If you have even a small greenhouse or cold frame, tomatoes will perform significantly better under cover. The extra warmth and protection from rain makes a huge difference.

Step 7: Harvest and Enjoy

Tomatoes are ready to pick when they're fully coloured and slightly soft to the touch. In the UK, you can expect your first ripe fruit from mid-July through to October, depending on variety and conditions. Cordon types keep producing right up until the first frost, so don't pull them out too early.

Pro tip: if autumn cold is threatening and you still have green fruit on the vine, pick them all and ripen indoors on a sunny windowsill. They won't taste quite as good as vine-ripened fruit, but they'll still be far better than anything from a supermarket.

Recommended Kit for UK Container Tomato Growing

Here's the gear I personally use and recommend:

• Fabric grow bags (5-pack) — lightweight, excellent drainage, fold flat for storage
• Multi-purpose compost (50L) — mix with perlite for best results
• Tomorite tomato feed — the UK classic, reliable and affordable
• Tomato support cages — perfect for bush varieties in pots

Frequently Asked Questions

Can I grow tomatoes in pots on a north-facing patio?

Tomatoes need at least 6–8 hours of direct sunlight. A north-facing spot in the UK is unlikely to give you a good crop. Try a south or west-facing location instead.

How many tomato plants per pot?

One plant per pot for indeterminate (cordon) varieties. You can fit 2–3 bush plants in a 20-litre grow bag, but more than that and they'll compete for nutrients.

Why are my tomatoes not setting fruit?

Common causes: temperatures too low (below 13°C at night), poor pollination (give the stems a gentle shake to release pollen), or excessive nitrogen feeding which promotes leaf growth over fruit.

When should I start feeding?

Only begin tomato feed once the first flowers appear. Before that, the compost provides enough nutrients. Feeding too early can cause leggy, leafy growth with no fruit.