GARDENING: ‘Why it’s wise to pot on tomatoes’

By Sally Gregson

AT last, the warmth has returned to greet the summer, and many gardeners’ thoughts are turning to growing tomatoes, aubergines and peppers in the greenhouse.

The frosts are past and the world, and the soil, is warming up. With a few days of sunshine these soft vegetables will respond with a growth spurt.

Having bought young plants, or raised them from seed in the frost-free greenhouse, it can seem like a good trick to avoid the task of regularly potting on fast-growing tomatoes in particular, by skipping the pot sizes and planting the young tomato straight into a bigger pot.

But putting small plants into big pots causes more problems than it solves.

The roots of young tomato plants tend to move outwards, seeking the sides of the pot where the moisture has evaporated down the inside. They tend not to grow into the middle of the compost.

Consequently, there is a whole area of wet, nutrient-rich soil that is sitting underneath the middle of the young plant. In extreme cases this can cause the whole plant to rot.

And the container is full of nutrients that are going to flush through unused, and they have a fairly short shelf-life.

It is much wiser to pot on each time the roots are showing through the drainage holes at the bottom, into a slightly larger pot.

It needs doing perhaps every two or three weeks, when the nutrients have been used up and the roots have absorbed all that moisture.

By the middle of June, the tomato plants will be big enough to plant out in a prepared, sunny spot in the vegetable garden, or into a grow-bag.

They will need feeding regularly from the moment they start to form flowers with a high potassium, tomato fertiliser to promote lots of fruit.

The days of tomato soup are back again.

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