What seeds can be sown in May?
In May the soil is beginning to warm up although there is still a risk of a late frost in some areas.
So, what can be sown in the garden and indoors in May?
Cabbages, cauliflowers, sprouting broccoli, sprouts, kohl rabi, swedes, turnips and broccoli
Now is your last chance to sow many of your brassica family although you can keep planting kohl rabi, sprouting broccoli and calabrese through until July.
If you want to be harvesting Brussel Sprouts in time for Christmas tthen get them in the ground!
Cabbages and cauliflowers should also be planted before the end of the month.
All brassicas (except spring greens) like a bed that has lots of organic material and will benefit from a natural fertilizer.
They also benefit from crop rotation to prevent soil-borne diseases. It’s best to avoid planting brassicas in the same area for 3 years if possible.
You can sow your brassicas indoors or directly outside if your bed already has space for them. Otherwise plant closer together in a seed bed and transplant them to their final growing position when it becomes available.
Cucumbers, courgettes, pumpkins, and other squashes
Squash and courgette seeds like the soil to be around 21 to 35 degrees Celsius (70- 95 degrees Fahrenheit) so they won’t germinate on a cold windowsill. Sow seeds indoors to increase germination success.
They may still require a heatpad or clear bag over the top to get them warm enough. If they’re not coming up then you can pop your pots in the airing cupboard to warm them up and remove them as soon as the seedling emerge.
Seedlings will be planted out next month when temperatures are consistently warmer and all risk of frost has gone.
Cucumbers on the other hand have a preferred germination temperature of around 16 – 35 degrees Celsius so can be sown outdoors after risk of frost has past.
For a continuous supply of fresh leaves then succession sow salad leaves, lettuces, spinach, swiss chard and oriental leaves like mizuna.
If you want to harvest the entire lettuce (with heart) then you’ll need to sow every 10 -14 days.
However, you can get away with only 4 or 5 sowings by picking only the outside leaves and leaving the plant to grow. To use leaves in this way you can sow seeds indoors in February/March and then outdoors at the end of May/ June and again at the beginning of July.
You’re final sowing will be in early September and will remain undercover for a fresh supply of winter salad leaves.
Maincrop peas, sugar snaps and mangetout
Peas are a cool weather crop so they can withstand some cold temperatures. They will still need covering if frost threatens.
During May you can continue to sow maincrop peas, mangetouts, and sugar snap peas outdoors.
Birds love to eat young shoots so cover with a net to protect them.
French beans and runner beans
These beans are tender crops and are not at all frost hardy so seeds are best sown indoors in early May (end of April) for an early crop.
You can sow one bean per pot 5cm (2in) deep and harden off before planting outside at the end of May/begining of June.
Later sowings can be made directly outdoors.
They will thank you for adding some well-rotted manure to your bed before sowing!
Climbing varieties will crop until September so one sowing is fine. However, dwarf beans will only crop for a few weeks so you’ll need to succession sow to ensure a supply of fresh beans (sow outdoors in June and July, for an early autumn crop).
There is little to be gained from sowing warm-climate plants too early in the year when soil is cold.
Towards the end of May sow sweetcorn seed directly or plant seedlings out when they are around 4-6in (10-15cm) high.
Choose a sheltered and sunny spot and plant in blocks rather than rows for successful pollination.
Although chillies and peppers are best sown early in the year (to ensure a crop this Summer) however you can actually sow seeds throughout the year.
Most chilli and pepper plants can be treated as perennial house plants (they will need some pruning in the winter).
Some varieties are more suitable as house plants than others so choose a small variety and find a sunny spot that gets plenty of light. (You will need a mixture of sunlight and fluorescent bulbs if you expect fruit though the winter.)
Carrots, beetroot, parsnips, swedes and turnips
Carrots, beetroot and parsnips can be sown anytime from April to June or July. If the weather is cold then beetroot will benefit from a cover to improve germination rates.
To sow make a shallow drill about 1cm deep and lightly sprinkle seeds in rows that are about 15cm apart.
Beetroot can be multisown in modules to save space.
Root crops prefer a stone free soil so prepare your bed beforehand. Avoid sowing in cold or wet soils as the seed is liable to rot.
You will need to protect against carrot fly by covering in a fine mesh net and only thinning and harvesting your carrots on still days and in the evening as carrot flies are attracted to the smell of disturbed leaves.
Swedes, and turnips are infact brassicas (the cabbage family) so should be planted in the same rotation as them and not returned to the same spot until the fourth year ideally.
You can still plant maincrop potatoes in May. They’ll be ready to harvest around 20 weeks from planting and tend to produce larger potatoes that are ideal for baking and roasting.
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