Gardening by month
Gardening in May
Spring has been slow to arrive this year, with more than its fair share of false starts during April. So far it has not been a easy year for gardeners, who have had their patience tested by such variable weather. Occasional days in late April were warmer than we often have at the height of the summer, but there were too many cold ones for our liking. The weather seems to have been erratic and unpredicatble through April
May is the ‘in between’ month for most of us, especially if we are growing tender (half-hardy) flowers for our beds, borders and containers. It is important to harden plants off (gradually accustom them to outdoor conditions), after they have enjoyed the protection of a greenhouse or polytunnel, but at the same time we need to be wary of late frosts, which continue in this part of East Anglia until the end of May. It’s a balancing act, and it is always a shame when a late frost nips tender plants which we have been nurturing for weeks.
Plant up hanging baskets and, if possible, grow them on in the greenhouse during May so they become well established before going outside towards the end of the month. Remember that at all stages of the plants’ development in baskets they will need plenty of moisture to prevent their roots being dried out by warmth and wind. All plants in containers will benefit from regular feeding in the weeks ahead. with a good quality plant food.
Hardy annuals which were sown direct in their flowering positions during March and April may now require thinning out to allow them to develop into good sized plants. There is still time to make further sowings of seed of hardy annuals to produce plants which will flower later in the summer.
As sweet peas grow, they will need to be tied in occasionally to their growing frame. They cling naturally, but a little help now and again is a good idea to keep them growing upright. Do keep an eye open for aphids (greenfly) on sweet peas and for other pests on ornamental plants.
Seedlings produced from later sowings of half-hardy annuals should be transplanted into other trays or cells to allow them to develop further before planting out at the end of the month. Use a good quality multi-purpose compost and plant the seedlings at the same depth as in the tray from which you are taking them. Water them well after transplanting with a watering can with a fine rose attached.
Seed of biennial flowers such as wallflower, sweet William, Canterbury bells and foxglove can now be sown either in seed beds in the garden or in trays of compost. The resulting young plants can be grown on steadily through the summer before being set out to their flowering positions in autumn ahead of flowering next spring and early summer.
If you have been raising tomato plants, these can now be planted out to growbags or the greenhouse border. Most tomatoes grown in the greenhouse are of the ‘indeterminate’ type, which means they need support from canes or wires and the regular removal of side-shoots if they are to produce a worthwhile crop. Bush tomatoes for outdoor cropping are ‘determinate’ and do not need support or side-shooting. Remember, though, that many indeterminate types can also be grown outdoors, if desired, but will still need support and side-shoots removed.
Lettuces and other salad leaves are perfect for successional sowings to keep you supplied with succulent salads right through summer and into autumn. Sow little and often to avoid a glut and the risk of plants running to seed before you have had chance to harvest them. Herbs such as coriander, chervil and basil can also be treated similarly.
As the month progresses, seed of tender vegetables such as runner beans, French beans, sweet corn and courgette can be sown direct in their cropping positions. Remember, however, seedlings will benefit from protection with fleece or newspaper on nights when frost is forecast. For surer results, seed can also be sown individually in pots of compost and placed in a greenhouse or cold frame. Germination rates will usually be higher and this method also gives the plants a head start when they come to be planted out later in the month or in early June depending on their maturity.
As the temperatures rise, weeds always seem to grow more quickly than our crops. It pays to keep these at bay either by careful hoeing or by hand weeding so that your young vegetables plants have as little competition for moisture and nutrients as possible. Annual weeds can be added to the compost bin, where they will soon rot down. Remember to thin out carrots, beetroot and other direct-sown crops to allow those plants which remain to grow larger. The thinnings can often eaten rather than discarded.
Straw placed under strawberry plants will help to keep the fruit clean as it develops and will also help to prevent botrytis. Straw also discourages slugs and snails from finding your fruit. As the fruits swell and begin to ripen, net the plants if possible to avoid the berries being taken by wild birds.
Where fruit bushes and trees are being grown in containers, give them plenty of water during this month. This is vitally important for those which are newly planted. Never rely on rainfall alone to supply all the moisture container-grown plants require. Give such plants a thorough soaking whenever the surface of the compost starts to feel dry.