How many tomato plants per grow bag?

Most gardeners put 2 tomato plants per standard 40L grow bag. Three is possible but restricts root space and increases watering needs.

Do grow bags need drainage holes?

Yes. Cut slits in the underside or poke drainage holes. Without drainage, roots sit in waterlogged compost and rot.

One growing season for heavy feeders like tomatoes. The spent compost can be used as a soil conditioner or mixed into borders.

Not for the same crop (disease risk). You can grow a lighter feeder like lettuce in year-two bags, or add the compost to your garden.

Two to three tomato plants per standard grow bag (40L). Two gives better results with larger fruit. Three works but needs more feeding and watering.

Calculate how many grow bags you need and plants per bag.

Number of Plants

Crop

Grow bags needed = Number of plants ÷ Plants per bag (rounded up).

Standard grow bag is 40 litres. Plant density: Tomatoes 2/bag, Peppers 3/bag, Courgettes 2/bag, Strawberries 5/bag, Lettuce 8/bag.

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.