What to plant and sow in May

Sowing vegetable seeds directly in the ground means you won't have the hassle of transplanting at a later date: the crop simply stays put from sowing to harvest. If you haven't already got them going in pots, courgettes, peppers, decorative gourds, pattypan squashes, cucumbers, gherkins and anything else from the melon family can now be sown directly. Sow in clusters of 3 or 4 seeds; you can later thin down to the two most promising plants in each cluster.

If there is still a chill in the air, these plants should be covered by a mini polytunnel, a polythene cover (until they germinate) or any other kind of makeshift cloche you might want to use (such as plastic bottles). If the weather is really not great, it's best to keep these crops in the greenhouse. Now is also the time to sow all kinds of summer and autumn lettuces, 'cut and come again' lettuces, spring and summer turnips, carrots, radishes, parsnips, beetroots, garden peas, mangetout, spinach, chard, cardoons, fennel and rocket.

If the weather is fair, you can start sowing all types of beans (green beans, haricot beans and so on) from the beginning of the month. However, if you live in a cooler region, it's best to wait until the end of May. Space the seeds around 4-5 cm apart in rows or sow in pockets of 4 to 5 seeds leaving 40 cm of space in all directions. If you are growing climbing beans, make sure you put up teepee-style plant supports to support them as they grow.

May is your last chance to sow salsify seeds. At the start of the month, corn seeds can be sown in rows spaced 70 cm apart. Chicory can be sown throughout most of the year, but pay attention to the variety. 'Sugarloaf' and 'blue sailor' chicory will usually do well when started in May.

Make sure to start your Witloof chicory before the end of the month; this will give the large taproot the time to grow sufficiently in order to produce beautiful chicory leaves come summer.

May is the perfect time to sow a range of vegetable seeds that will be planted out at a later date and harvested in the autumn. The following vegetables can all be started in a polytunnel or greenhouse:

• Celery;

• Celeriac;

• Romanesco broccoli;

• Brussels sprouts;

• Cauliflower;

• Curly kale;

• Many varieties of cabbage;

• Swede;

• Kohlrabi;

• Winter leeks.

Now is the time to plant any vegetables that were started indoors: tomatoes, aubergines, chillies and peppers can all go in the ground at the end of the month. Anything belonging to the cucurbitaceae, or melon, family can also be planted out; this includes things like melons, cucumbers and squashes.

If your plants are looking cramped in their pots but you're still wary of frost, you can always transfer them to bigger pots where they will happily await the arrival of nicer weather. Plant out anything belonging to the cabbage family that appears strong enough (with the exception of Romanesco broccoli). Cauliflowers, green cabbage and sprouts broccoli, can either go straight in the soil or placed under mini polytunnels or cold frames until they gather a bit more strength. It's a good idea to leave these roots to soak for a full night in a root dip before planting in the ground.

Root dips can be easily made using a combination of cow manure, clay-rich soil and water. This mixture can also be used for celery, celeriac, chicory, chard and cardoons. Finally, you can still plant seed potatoes – especially late varieties you're planning to keep for winter storage.

Any potted herbs or aromatic plants, whether you've bought perennials or annuals, can go in the ground in May. This includes things like angelica, rosemary, mint, chives, spring onions, thyme, sage, tarragon, sorrel and basil.

Parsley, chervil, dill, basil, marjoram and borage seeds can all be sown. Sowing or planting in individual pots or planters can help you to save space and cut down on plant care (especially weeding). Growing in pots can also be decorative!

If you already have tarragon, mint, chives, spring onions and sorrel growing, now is a good time to divide your plants.

Looking to create visual interest in the garden as well as on your plate? Here are a few lesser-known plants that can be sown directly in the ground: New Zealand spinach, amaranth, Good-King-Henry, paracress, miner's lettuce and purslane.

Sweet potatoes can be grown under cover and are as decorative to grow as they are delicious! Yacón, or 'pears of the earth', are another type of tuber that can be put in the ground as soon as the last frost passes. They also keep really well so they're great for winter stews.

One final word of advice: if you've got crops growing in cold frames or under covers don't forget to let them breathe during the day as the sun can be unforgiving even in May!

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• Lawnmower buying guide

• How to make compost