Your vegetable garden in May 2013
Why not have a go at growing in a pot this year? You’ll find lots of helpful advice on the One Pot Pledge growing cards. A great way of adding to your growing space. A tray of salad on a windowsill, for example, can give you some fresh greens in just a few weeks. http://www.onepotpledge.org/pdfs/mixed_salad.pdf
May is the month of the infamous 'Hungry Gap'. Sowing and planting of vegetables is reaching its height - but pickings are rather slim. Ideas and tips to avoid disappointing gaps during this period can be found in our 'Banishing Gaps and Gluts' factsheet.
The weather in May could do almost anything. Your local weather may well be different to ours at Ryton Gardens. Keep some fleece (or net curtains, sheets of newspaper or whatever) to hand to pop over plants to protect them overnight if frost is forecast. But remember to ventilate (and water) greenhouses, tunnels and cloches if it turns hot.And don’t be tempted to put tender plants such as French beans and cucurbits out too early, better to wait until all risk of frost is past rather than lose them.
- Sowing outdoors
- Pest and disease watch
Frost damage on potato leaves
Local grown plant supports
cabbage undersown with
- Prepare a runner bean site by incorporating manure or garden compost into a trench, one spade deep. Tie in beanpoles, either in a wigwam shape or the traditional double row of opposing poles with a horizontal strut at the top to add strength and rigidity. Source locally coppiced stakes such as strong hazel poles to make an alternative to imported bamboo canes.
- Continue cutting asparagus spears.
- Fill empty gaps with cover crop green manures, such as fast growing buckwheat, mustard, phacelia or trefoil that can all be sown in May if the ground is moist enough. There are plenty to choose from to suit your soil and unique growing conditions. See our Get started guide, Green Manures (requires members' password) or purchase the Garden Organic 'Gardening with Green Manures' booklet.
- Green manures seeds are available from The Organic Gardening Catalogue.
- Sow nitrogen fixing trefoil around sweet corn or overwintering brassica plants. It will grow in the shade of the plants, helping to keep weeds under control. In the autumn, cut down the sweetcorn, leaving the trefoil in place to grow over winter. This is an easy way to establish an overwintering green manure and provide soil fertility for following crops in the the spring.
- Hoe regularly to keep down weeds. For more information on weeds go to our Organic weed control section.
- As the soil continues to warm towards the end of the month, you can begin to plant out some of the more tender crops, and to sow them directly. A good start makes all the difference to how they will perform eventually.
- Support peas with twiggy sticks or pea netting.
Growing conditions can vary dramatically across the country, and also even within a locality. If you are new to growing and are unsure about exactly what to do when, try asking other vegetable growers nearby. And be guided by the weather and soil conditions.
Beetroot, carrot, lettuce
and pea (4 weeks old)
Do you know your seedlings? Test your knowledge with our mini quiz
Lots of places sell veg plants these days, so you don’t have to grow your own. Delfland Nurseries sell organic, peat free plants on line, including a range of our Heritage Seed Library tomatoes. A donation goes to Garden Organic for every pack sold. Last delivery - early May.
M* *These crops may also be raised in modules for transplanting. M Beetroot Early and maincrop; until July M Calabrese Until end of July Carrots Early; until end of July Carrots Maincrop; until end of June. Sowings made in June should miss the main flight of the carrot rootfly. Chickpeas Until mid-June Click here for more information. Fenugreek (methi) Until August. Click here for more information. Haloon Until September. Click here for more information. M Kohlrabi Until August M Lettuce Loose leaf, Cos, crisphead and butterhead. Lettuce, apart from crisphead varieties, doesn’t germinate well when the soil temperature goes above 25°C. This can happen in summer. In hot weather, sow into modules or seed trays and shade from the sun. Salad onions Until mid June; sow winter varieties from August onwards. Peas Maincrop, mangetout and sugarsnap [ until end of July]. Where pea moth is a problem, delay sowings until mid May, so they will be flowering after the pea moth lays its eggs. Salsify Until end of May Scorzonera Until end of May Spinach Summer; until end of May
Sow runner and
French beans direct
M* *These crops may also be raised in modules for transplanting. M Amaranth (Calalo) Sow outside from 2nd week in May till July. Click here for growing information. M Courgettes, marrows and pumpkins Where cucumber mosaic virus is a regular problem grow courgette and marrow varieties that are resistant. Pumpkins tend not to suffer from this disease. Minimum soil temperature 13°C. M French beans, dwarf or climbing For eating fresh; sow until end of June, or July with protection (dwarf only). Minimum soil temperature 10°C. M French beans, dwarf or climbing, for drying For drying, choose specific varieties. Check out French bean varieties in The Organic Gardening Catalogue. Sow as early as possible to give a long growing season. In cooler areas, start off in pots. Minimum soil temperature 10°C M Runner beans
Sow until early July. Best transplanted from deep modules or ‘rootrainers’ where slugs are a problem. Minimum soil temperature 10°CThe dwarf runner bean variety Hestia avoids the need for tall supports and can be grown in containers.
M Florence fennel Choose a cultivar such as Finale or Romanesco that is suitable for sowing before mid June; some cultivars are very sensitive to daylength and will bolt if sown before the longest day (21st June); sow until early August M Sweetcorn Sow until early June; minimum soil temperature 10°C. M Swede Until early JuneTemperature tip
Sweetcorn, courgettes, marrows, pumpkins, cucumbers, tomatoes, French beans and Runner beans are temperature sensitive crops. If they are sown in soil that is too cold, germination will be poor, and any seedlings that do appear will not crop as well as those started in warmer soils. The critical period is when the seeds are taking up water in order to start the germination process. Once this is complete, lower temperatures are acceptable.
See individual entries for temperature requirements.
M* *These crops may also be raised in modules for transplanting. M Leeks last sowings in early May M Cabbage autumn and winter varieties M Cauliflower autumn and winter varieties M Sprouting broccoli until mid May M Kale (borecole) until early August
To make a seed bed:
- Choose an area – a corner of your vegetable plot for example
- Remove weeds and rake soil to a fine tilth. Disturbing the soil stimulates weed seeds near the surface to germinate.
- Leave the prepared seedbed for 2-3 weeks, watering it if dry. Lightly hoe off the emerging weeds. Sow immediately into the prepared, weed free bed. This is often called the ’stale seedbed’ technique.
Sow in trays and modules
Vegetable Minimum soil temperature Beans, French and runner 10°C Courgettes 13°C Cucumbers 13°C Lab Lab bean 18-21°C Melon 13°C Sharks fin melon 13°C Sweet potato slips 12°C Pumpkins and squash 13°C Sweet and chilli pepper 15°C Sweet corn 10°C Tomatoes 10°C
Always 'harden off' young plants that have been raised indoors, in a greenhouse, or under a cloche, before planting them out. This means gradually getting them used to the outdoors, so they develop a thicker 'skin', before they are planted out. This will help them withstand the cooler, drier, windier conditions outside, and they will grow away quickly.
To harden off plants, put them outside in a sheltered, not too sunny, spot during the day for a few days, then leave them out overnight for a couple more. If the weather is very wet or windy, try and rig a temporary roof for protection.
Don't plant out frost tender crops until after the last frost. As this is not always easy to predict, have some temporary protection (cloches, fleece, sheets of newspaper) available to cover plants over night if frost is likely.
Protect against carrot fly – a
70cm high barrier can reduce
infestation by carrot fly.
Cabbage white butterfly
eggs and caterpillars
Weevil notched broad bean leaf
Brassica collar to protect
young cabbage plants
from cabbage rootfly
Blackfly (the black bean aphid) first appears on the shoot tips of broad bean plants.
Check plants regularly and squash any blackfly seen. If the plants are flowering, pinch out the top couple of inches, blackfly and all. You may find that one or two plants, often at the edge of a plot, become very badly infested, with the pests on flowers and pods too. It's best just to remove these plants and bury them in the compost heap. If necessary, spray with insecticidal soap - spraying the pests directly.
Protect carrots, parsley and parsnips from carrot rootfly in areas where this pest is a problem. Our carrot rootfly factsheet tells all.Find out about becoming a Garden Organic member here
When you see cabbage white butterflies on the wing, start checking cabbage and other brassica plants for signs of eggs and caterpillars. Squash or pick off any you see.
Flea beetles are pests of Brassicas (the cabbage family), radish, mustard and other related plants. They are particularly damaging to young seedlings, especially during dry weather. Check our Flea beetle factsheet for advice on protecting plants. Factsheet requires members' password.
Put out slug traps around new sowings and plantings - preferably a week or two before sowing or planting. Or treat the ground with Nemaslug.
Pea and bean weevils eat little notches out of the edges of peas and broad bean leaves. The damage can look awful, but plants usually survive and grow away from the damage. Water plants to encourage growth in dry conditions.
Protect young cabbage and other Brassica plants from cabbage rootfly from the moment they are planted out. Brassica collars are very effective (see picture).Plant collars are available from The Organic Gardening Catalogue