Your tomato plants have survived the great outdoors test — the wind, the temperature swings, the unpredictable British weather — and they're hardened off and ready to grow. Now comes the exciting part. But before you just plonk them in the ground and hope for the best, there are a few things that will make the difference between a handful of tomatoes and a genuinely impressive harvest. Get these four things right and your plants will reward you all summer long.
Choose a Big Enough Container (Seriously, Go Bigger)
This is the number one mistake home growers make, and it's an easy one to fix — but only if you catch it before planting. Tomatoes are hungry, thirsty plants with extensive root systems, and when they're cramped in a small pot, they struggle. You'll see it in the leaves first: yellowing, wilting between waterings, and stunted growth even when you're feeding regularly.
For a single cordon (upright) tomato plant, you want a minimum of a 30–40 litre pot. Bigger is genuinely better here. A larger volume of growing medium holds more moisture, buffers temperature swings, and gives roots the space they need to support heavy fruiting trusses above. If you're growing in a raised bed or directly in the ground, aim for at least 60cm depth.
Fill with a high-quality peat-free compost — ideally one blended for containers or enriched with perlite for drainage. A well-aerated root zone is just as important as pot size.
Get Your Support in Place Early
Tomatoes don't stand up on their own — at least not for long. Once they're in their final position, get your support structure in place immediately, before the plant gets any bigger. Trying to stake a 1.2m plant without damaging the roots or snapping stems is a frustrating experience you don't need.
For cordon varieties, a sturdy bamboo cane (at least 1.5–1.8m) or a purpose-built tomato spiral stake works well. Tie the main stem loosely to the support as it grows — use soft ties or old tights rather than wire, which can cut into the stem. Check and adjust ties every week or two as the plant puts on height.
If you're growing bush (determinate) varieties, our Collapsible Circular Plant Supports placed over the plant early on will keep the sprawling growth contained and off the ground.
Feed Consistently and at the Right Time
Once your tomatoes are in their final pot or bed, they'll quickly exhaust the nutrients in fresh compost — usually within four to six weeks. After that, regular feeding is non-negotiable.
For the first few weeks after transplanting, while the plant is establishing and putting on leafy growth, a balanced feed works well. Once you see the first flowers forming, switch to a high-potassium tomato feed. Potassium drives flower set and fruit development, so this is the stage where it really counts. We recommend Growth Technology Tomato Focus – Organic Liquid Fertiliser — a specialist formula designed specifically for tomatoes and fruiting crops.
Feed every seven to ten days throughout the growing season, following the product's recommended dilution rate. Don't be tempted to double-dose — more isn't always more, and overfeeding can cause nutrient lockout or leaf scorch. Consistent, regular feeding at the right rate will always outperform sporadic heavy doses.
If you're growing in a hydroponic or coco medium, you'll need a dedicated nutrient solution from the start, as these substrates contain no inherent nutrition.
Pinch Out Side Shoots (Cordon Varieties Only)
If you're growing a cordon (indeterminate) tomato variety — which is most of the classic types like Gardener's Delight, Alicante, or Sungold — pinching out side shoots is one of the most important things you can do to keep the plant productive and manageable.
Side shoots are the small shoots that emerge in the "V" between the main stem and a leaf branch. Left unchecked, they'll grow into full secondary stems, the plant becomes a sprawling bush, and energy is diverted away from fruit production.
Check your plants every few days and pinch out any side shoots when they're small — ideally under 2.5cm. At that size, you can simply snap them off cleanly with your fingers. Larger side shoots are better removed with a clean, sharp blade to avoid tearing the stem.
Important: this only applies to cordon varieties. If you're growing a bush or dwarf variety, do not pinch out side shoots — the plant's fruiting habit depends on that branching growth.
A Quick Summary
- Big pot — 30–40 litres minimum per plant; don't underestimate root space
- Support early — stake before the plant needs it, not after
- Feed regularly — balanced to start, high-potassium once flowers appear
- Pinch side shoots — every few days on cordon varieties, keeping them small
Get these four things dialled in and you'll have strong, productive plants that fruit well into autumn. Next up in the series: recognising common tomato problems and how to fix them before they set your harvest back.