Anna Pavord: Want the salads to keep coming and the flowers to keep blooming? Here's how...

Enhance their performance: New shoots of wisteria (Alamy)

TOP JOB FOR THE MONTH

Successional sowing: the alliteration soothes like a lullaby. We sort of know what it means. We understand the principle. It's putting it into practice that's the problem. Partly, this is because of the great orgy of seed sowing that – if you grow vegetables – marks April and early May. Been there, done that, you say to yourself. And perhaps you have. The carrots are doing nicely. Chard is filling out in a satisfactorily juicy way. You've already munched a few crops of pea tips. Radish have been gathered to plunge into hummus. Spring onions are there for the taking.

But unless you start all over again with the seed sowing, those crops will have run out by the end of the month. And I haven't even mentioned salads: chicory, lamb's lettuce, baby kale, rocket, sorrel and the various leaf mixes that provide quick cut-and-come-again greenery. We are coming into July with conditions that are ideal for seed sowing. That is one advantage, perhaps the only advantage, of the rain we had earlier in June. There is still moisture locked up in the ground. If you grow your vegetables on sandy, fast-draining ground, water the seed drill before you sow.

All the vegetables I've listed can be grown in containers, as well as the open ground. In fact, you are surer of a crop in a container, if you remember to water. The compost will run out of steam in about six weeks, and then, with slower crops such as carrots, you will have to add a liquid feed to the watering can. But successional sowing is a technique that only applies to relatively fast-growing summer vegetables. The whole point is that you keep a fresh supply coming on and abandon the earlier, and by now scraggier crops.

In a small garden, it's a waste of valuable space to have gluts of food that you can't use quickly enough. Far better to get into the habit of sowing little and often. If you are sowing in containers rather than the open ground, there is a natural limitation on the amount of seed you can sow at any one time. Very quick crops such as radish and cut-and-come-again salads will work in a pot only 28cm/11in across. But don't expect successional sowings of baby turnips or beetroot to do well in a container that small.

Some crops, such as spinach, can be used in two ways, as baby leaves or as full-grown greens. In the open ground, you can leave the crop you have been harvesting for salad to grow on to maturity. But July is not a good month to start fresh crops of spinach. It tends to bolt if the weather is hot and dry. Leave successional sowing of this crop until late August or September.

FIND TIME TO

Prune wisteria: We prune plants because we want to enhance their performance by way of flowers, foliage or fruit. It's for our benefit, rather than theirs. So if a plant flowers on new wood, rather than old, cutting off its new growth each year is not a good idea. Wisteria flowers on old wood. But after it has flowered, it throws out jungly, long tendrils of leafy new growth. Choose the ones that you want to keep and tie them in to supports (parallel wires are ideal). After whatever space you have in mind has been covered by these new shoots, you need to be brutal with the rest, so the plant puts its energy into making potential flower buds on the old wood, rather than expending it on leafy new stuff. This month, shorten any young growths that you do not want to keep, cutting them to within five or six buds of their starting points. Next February, you can cut these back even further, leaving two or three buds at most. At that stage, when the stems are bare, you will be able to catch up on all the tendrils that you miss now. You will also be able to haul exploratory stems from under roof tiles and fascia boards, where they can develop into nuisances.

Successional sowings of beetroot (Alamy)

Control self-seeding by cutting down stems of over-enthusiastic plants such as columbine. You don't want to stop self-seeding entirely – it's a cheap way to fill up a garden and columbines, particularly, are welcome because their glaucous grey-green foliage is as good as their flowers. Self-seeding also introduces new colours and forms of a plant into a garden. Hidden away in a columbine's gene pool is a wide range of possible colours and forms. Without ever introducing a white-flowered variety, I now have quite a few plants of them, which have been very welcome over the past six weeks. Cutting down clumps of very vigorous plants such as columbine, rocket and alchemilla also creates room for other plants to stretch out their elbows. Forget-me-not should be pulled up entirely. It's not worth keeping plants for the sake of the new growth in the centre of the old clumps. Plenty enough seed will already have been spread by the forget-me-nots and these fresh plants will have more vigour than the old ones.

THINK ABOUT

Deadheading: I fantasise about dead-heading. It will happen in some rosy future, when I can wander about the garden in a straw hat with nothing more pressing on my mind except the need to tweak spent violas from well-tended clumps. Certainly it is a good thing to do and will prolong their flowering. You can usefully do the same thing with pinks. Annual larkspur will (like delphiniums) flower on side shoots if you cut out the main stem when it has finished its performance.

Lift garlic as soon as the leaves begin to wither. Allow the bulbs to ripen outside (weather permitting) as you would onions. You can then clean up the bulbs, plait them into strings and hang them in a cool place.

TO VISIT

Gardens open this weekend include architects Deborah Nagan and Michael Johnson's productive plot at 225A Brixton Road, London SW9. Raised beds of vegetables in the front garden, fruit at the back with a calm space beyond with pool and fish. Open today (2-6.30pm), admission £3.50. Open tomorrow (2-6pm), for the first time, is garden designer Joanne Bernstein's own place: contemporary prairie-style planting, with a woodland area beyond. Admission £4. This evening, music, wine and candles fill the garden at Stane House, Bignor, Sussex RH20 1PQ, organically-grown crops, a herb garden and generous herbaceous borders looking out over the South Downs. Open 6.30-10pm; also open tomorrow (11am-5pm), admission £4.