Vegetable planting should now be well under way, if ground conditions permit. Try not to stand on the ground when planting, as this compacts it; instead, use planks to make walkways between your plots and rows. If your garden is small, you may have followed the ‘no dig’ idea, whereby the life in the soil aerates it naturally. By clearing the ground in autumn and spreading compost and manure on the surface, the worms take them down themselves and you prevent leaching of the nutrients in the bare soil through the winter. A larger garden can use the same idea, but you might find it economical to use a mechanical rotovator to prepare the soil for the spring planting.
Sow summer cabbage and Brussels sprouts now. All ours are sown in 40-cell plug trays under glass to avoid the problems of traditionally sown seeds in outside drills, where germination can be erratic and the seedlings are vulnerable to flea beetles, slugs and snails. Sow one or two seeds to a cell, keep in a cold greenhouse and plant out when about 5in–6in tall. The plugs are easy to plant out using a dibber. If the planting is delayed, brassicas respond well to liquid feed
For tall sprouts, vulnerable to the wind, dig out a spade’s depth of soil and plant the plug in the bottom. As it grows, the hole can be filled in, as the sprout will produce roots up its stem and anchor the plant.
Now is a good time to sow sweetcorn indoors. To avoid root disturbance when planting out, sow two or three seeds to an 8cm Jiffy pot, place on a heated bench Or in a warm greenhouse, and remove the weakest seedlings to leave one plant in each pot. You can plant them out towards the end of May. If you’re planting quantities, bear in mind that sweetcorn should be planted in blocks rather than rows to improve pollination. Try an F1 hybrid early-maturing super-sweet variety, which, although not available as organic seed, is reliable, and the compact size is helpful in small kitchen gardens.
Consider sowing one of the tall-growing nasturtiums, such as Jewel of Africa—these are great for underplanting and covering the ground, especially if planted under sweetcorn as a weed suppressant.
Dahlia tubers should be potted up in a warm greenhouse to encourage new growth, ready for planting out when the risk of frost has gone. If the tubers have already started to grow, think about using the new growth for cuttings to increase your stock.
We find the soft new growth of summer-flowering clematis quite vulnerable to wind at this time of the year, even in our walled gardens. Take a little bit of time now to tie back the new growth to its support, to encourage the plant to grow upwards and flower where you want. Philip Maddison is head gardener at Harrington Hall, Lincolnshire (www.harringtonhallgardens.co.uk)