Potting on tomatoes and planting ornamental rhubarb

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Our gardening columnist Mandy Watson gives tips on growing your own tomatoes

IT’S time for my favourite job of the year – potting on greenhouse tomatoes.

There’s nothing like the glorious smell of the leaves to conjure up the summer (apart from a pint of wheat beer).

Despite what many people think, tomatoes aren’t difficult, if you give them sun, food, support and plenty of water - pretty much what you’d like for a summer holiday.

I grow cordon varieties Gardeners’ Delight, Super Roma and Suncherry from seed sown in mid-February and their first trusses are now flowering.

Cordon just means grown on one stem – you have to nip out the sideshoots to encourage the plant to fruit more.

The advantage for me is that I have a long, thin conservatory, so they don’t take up too much space horizontally.

I use ring culture (bottomless) pots screwed into large growbags.

This gives them a much larger area to develop a healthy root system and they don’t dry out so much.

Using three plants per bag, the pots are filled with good-quality peat-free compost with a water-conserving gel added to stop them drying out.

Plant them deep – past the seed leaves – as the stems root readily.

It’s important to stake cordon varieties when planting, to avoid damaging the rootball.

Use two 5ft canes per plant and lash them together so they’re secure.

My growbags sit on a shelf in trays, which gives them 5-6ft before they hit the roof.

That’s an ideal space for them to develop four-six trusses.

It’s important to nip out the top of the plant then, so all the plant’s energy is concentrated on ripening the fruits.

It’s also helpful to remove the bottom leaves and any that are covering trusses as the plant matures.

Don’t start feeding until the first truss has set – after that, once a week is fine - but don’t forget to water virtually daily in the heat of summer.

PLANT OF THE WEEK – Ornamental rhubarb (Rheum palmatum)

Every week, I’m going to pick something that’s really earning its keep. The ornamental rhubarb I have by the pond is looking stunning, with its massive, dark green and purple leaves – and that’s before it’s flowered!

It’s ideal for an exotic look, but is fully hardy and undemanding. It’s leaves can look tatty by the end of summer and on no account pick it - it’s very poisonous.