Best grow bags for summer salads in 2023

If your tomato plants struggle to give you a great crop, the problem might well not be how you grow them, but the compost they're growing in. 

Grow bags are an easy way to grow summer crops such as tomatoes, cucumbers, chillies, peppers and aubergines. You don't need a greenhouse, just a sunny spot such as a patio.

However,  grow bags have traditionally been a pile-it-high, sell-it-cheap option made with peat compost, which is low cost and readily available. With the ban on peat compost coming into force from next year, more manufacturers are creating peat-free alternatives.

Which? Gardening magazine tried 10 different grow bags to find the best. Discover our Best Buy grow bags.

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Best grow bags

We tested peat-free grow bags, as these are becoming more common. By the end of 2024, peat compost will be banned for sale in garden centres, so now is the time to make the switch from peat. 

We tried 10 peat-free grow bags to find the best ones for your tomato, cucumber and pepper plants.

We counted how many cucumbers were harvested from each bag and weighed them. From this we calculated the mean weight of cucumbers for each brand. We also graded the plants for vigour (their general health) and the size and colour of the leaves.

There were two Best Buys that grew outstanding crops of cucumbers, growing more than twice as many as the lowest-scoring bag. 

How to use a grow bag

Grow bags are great in the greenhouse, but you can also use them in any area of the garden that's in sun for most of the day. 

• Place the bag where you want to grow your plants, then roll it gently to fluff up the compost inside. Make a few slashes on the base to let excess water drain away. 
• Most bags show you where to cut holes to plant into the bag. The number of plants you can fit into one bag varies according to what you're growing and the size of the bag. Check the instructions on the bag. 
• Summer veg can be grown from seed or bought at the garden centre. In either case, you'll need a Best Buy compost for seeds or for raising young plants. 
• Your veg can be planted in the bag when they're around 15cm tall. Remember that most summer veg, including tomatoes, cucumbers, chillies, peppers, melons and aubergines, aren't hardy. Don't plant them outside until mid to late-May, after the last frosts in your area. 
• Use a bamboo cane or a plant support to train your plants. Remember to water regularly and don't let the bags dry out between watering. You may have to water up to three times a day in hot weather, so think about using an automatic watering system. 
• Summer veg need regular feeding to produce a good crop, and most bags will need an additional feed. Liquid tomato fertiliser is great for all summer veg, as it has the right balance of nutrients. 

Look at our guide to the best summer veg for everything you need to know about how to grow and which varieties will give you bumper crops that taste delicious.