A grow bag is a mini garden in itself. It has many advantages over planting tomatoes directly in the soil or large container. Furthermore, growing tomatoes in grow bags is one of the most popular ways to grow tomatoes in the UK, and here are some reasons why!

The Benefits of Grow Bags

  • A grow bag is a self-contained, disease-free environment, giving young plants the best start.
  • A quality grow bag contains all the nutrients needed for the first six weeks of growth.
  • It cannot be blown over in the wind, unlike a large pot!
  • It contains enough soil for up to three tomato plants.
  • Grow bags help to protect plants against slugs, snails and other little critters who fancy a nibble!
Growing tomatoes In grow Bags using grow bag pots.

Best Tomato Varieties for Grow Bags

The ideal varieties to grow are tall, cordon, indeterminate tomato plants. These are plants that grow tomatoes on trusses, from one tall stem.

Tomato varieties such as Moneymaker, Gardener’s Delight and Shirley are all traditional varieties that are ideal for growing in grow bags.

Best Position for a Grow Bag

Because tall varieties need support, growing up against a fence or a wall is ideal. Support canes are used to support the tomato plants, then the canes are tied to the fence or a hook/nail on the wall.

Of course a sunny position is best for growing tomatoes but if your garden is facing north, put them in as light a position as possible. Cherry tomatoes will still grow successfully without full sun if the plants have plenty of light. A good cherry variety is Gardener’s Delight and Sungold is a popular very sweet orange cherry tomato.

When To Plant Out In Grow Bags

Plant out in grow bags after your last frost. In the UK, this is around the end of May but you can plant out mid-May if the weather forecast looks OK.

Young plants should be around eight to ten weeks old when planting out and sown in March. Of course you don’t have to start tomatoes from seed, garden centres will have a good selection of tomato varieties in March and April.

How To Plant Tomatoes In Grow Bags

Loosen Soil

When you get the grow bag home, you’ll find that the soil is very compacted. Give it a roll back and forward on the ground to loosen the soil inside. It’s important that the soil is loosened, before planting, so that plenty of air can get into the soil. This will help roots grow better if the there is plenty of oxygen between the soil particles.


Insert a pencil hole, two at each end of the grow bag so that excess water can escape. You won’t want your best tomato plants to be sat in watery mud on a cold night!

However, It’s important that the entire soil area is moist so that roots can absorb soil nutrients. Dry soil often leads to Blossom End Rot and other problems.

If holes are inserted in the middle/sides of the grow bag, water may escape before the whole soil area has been watered.


Make three holes, evenly spaced in the top of a grow bag about the diameter of a six to eight inch pot. Loosen the soil below, add a handful perlite if you have some, then push the soil below to the sides to make a good size hole.

Take the young tomato plant out of its pot, loosen its lowest roots slightly, then plant in the grow bag.

It’s not necessary to water the hole bag at first planting. Just give each plant around a pint of water. They won’t need more than that for a few days.

Growing Tomatoes In Grow Bags


Young tomato plants don’t require a lot of water. After the first watering, let them go for several days without more water, so that their roots grow and become established.

The more water roots have, the less air there is in the soil. Roots need water and air.

Also, roots grow in search of water, if given too much, the root area will be smaller and under-developed.

Grow Bag Optimization

  • Make sure that the soil is loosened before planting
  • Add drainage holes to each end of a grow bag
  • Include a handful of perlite for each plant if possible
  • Don’t over-water
  • Allow roots to develop and grow in search of water after first watering
  • Sink pots into grow bag for watering
  • Use grow bag pots to increase growth
Three grow bags with compacted soil.

To Sum Up

Growing tomatoes in grow bags is great way to get a very good result each summer.
One cherry tomato plant can produce hundreds of tomatoes, even outside, if grown well and with a bit of good weather too!

If you are new to growing tomatoes, I definitely recommend a tall cherry variety such as Gardener’s Delight. There are many other similar varieties available but the larger tomatoes are more difficult to grow.

See also: Grow Bags, Tall Varieties and Removing Side Shoots

Grow Bag Pots and Ring Culture

Next: Growing Tomatoes on the Windowsill