Growing Tomatoes in Growbags

Planting and spacing

Plant two tomato plants per standard growbag. Bush (determinate) tomatoes stay shorter and bushier and are the easiest choice for bags, needing little beyond watering and feeding. Cordon (indeterminate) tomatoes grow tall, up to about 1.8m, and are more productive per plant but need firm support and regular side-shooting.

• Two plants per standard growbag
• Bush (determinate) types are easiest and need little support
• Cordon (indeterminate) types grow to around 1.8m and need tall support

Watering rhythm

1. 1Keep it evenly moist — Water regularly so the compost stays evenly moist rather than swinging between wet and dry.
2. 2Water more in heat — Growbags are shallow and dry out quickly; in hot weather larger plants may need watering at least once a day.
3. 3Avoid fluctuations — Erratic watering causes fruit to split and contributes to blossom end rot, so aim for consistency.

Support and feeding

Cordon tomatoes need tying in to canes or a support pushed firmly into the bag, or a purpose-made growbag frame, because you cannot push canes deep into a shallow bag. Bush types usually manage without support unless a stem is heavily laden with fruit. Once the first fruits set, feed with a tomato fertiliser as recommended by the manufacturer to keep plants cropping.

✔ Because canes will not anchor deep in a shallow growbag, use a growbag support frame or run string up to an overhead wire for cordon varieties.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• RHS — How to grow tomatoes — Two plants per standard growing bag (one per 30-45cm pot); water regularly to keep compost evenly moist, at least once a day in hot weather for larger container plants; fluctuating moisture causes splitting and blossom end rot; cordon (indeterminate) tomatoes grow up to 1.8m and need tall supports tied to canes; bush (determinate) tomatoes are shorter and rarely need support; feed as manufacturer recommends.

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