As temperatures warm and days get longer, seeds become easier to sprout and seedlings will grow in front of your eyes on sunnier days.
There is loads of stuff you can sow now. Just keep an eye an eye out for those pesky slugs waking up after winter.
If you’re new to growing, this is one of the best times of year to start on your first growing projects!
Advice below is based on the UK climate. While it’ll be relevant for most other Northern hemisphere countries, exact sowing dates will vary from region to region. Look on Google for a seed sowing calendar for your neck of the woods and use together with the tips below.
- What you can sow outside
- What you can sow inside
- Other jobs: slug and snail purge, “potting up” tomatoes, rejuvenating old compost, acclimatising seedlings to outdoor conditions, starting a wormery.
1. What you can sow outside
The following can all be sown outside this month – either direct in their final pots or in modules or seed trays.
- Snap peas, mangetout and broad beans.
- Root veg: spring onions, radish, beetroot and carrots (you’ll need to start these in modules or in their final container as the baby plants do not like their roots to be disturbed).
- Salads: lettuce, rocket, and most other salad crops.
- Oriental greens: pak choi, mibuna, mizuna, mustard red giant etc. (‘Officially’ you should wait until after the summer solstice to sow most Oriental greens as the lengthening days at this time of year may encourage the plant to produce flowers rather than leaves. But I like them so much I can’t resist sowing some now – and you’ll still get a reasonable crop).
- Leafy veg: kale, swiss chard, and leaf beat. You can also sow spinach and traditional cabbages now – but I’ve always found leaf beat and Chinese cabbages to be easier and more productive in containers.
- Potatoes: if you sow ‘first early’ potatoes now, you should get a crop before the end of July. This will give you time to grow another crop – like runner beans or a courgette – in the same pot later in the year. When sowing potatoes before the last frost, cover the top of the container with clear plastic or horticultural fleece to protect the emerging shoots from any late frosts.
- Herbs: including coriander, chives, parsley, sorrel, lovage, dill. By the way, dill, coriander and chives all produce flowers that will attract beneficial insects.
2. What you can sow inside
Although it’s getting appreciably warmer this month, you still can’t sow the following tender plants outside until the risk of frost in your area has passed (‘tender’ means they’re killed by frosts). In the UK this is usually the end of April / mid May, depending on where you live (if you live in the UK, USA or Australia, you can find the date of the last frost in your region here).
- Tomatoes: you still have time to start tomatoes from seed – sow them as soon as you can – and by the end of the month at the latest.
- Runner and French beans: if you want an early crop, you can sow some inside now to move outside after the last frosts. Starting beans inside is also a good strategy to protect them from slugs. Slugs just love emerging seedlings!
- Courgettes, squash, cucumbers: sow these indoors this month if you want an early crop. These crops can grow big quite quickly so you’ll just want to check you’ve got enough space to accomodate them inside until the risk of frost in your area is over.
- Herbs: including basil and green perilla (a tasty Japanese herb, a nice alternative to basil).
You can, if you prefer, sow most of these crops outside next month once the risk of frost in your area is over. The one exception is tomatoes – as May is a bit late for most varieties – but you can always buy plants in May or June if you prefer.
3. Other jobs
Do a slug and snail purge
Before putting your precious seedlings outside, hunt for lurking slugs and snails in your growing space. Slugs love seedlings and can decimate a whole crop in one night. Look under pots, in cracks, behind any foliage (eg ivy or other evergreen creepers). The trick with slugs and snails is to keep on top of the population all year – and a purge early on will help a lot. A few not do little harm, but a population out of control will quickly get demoralising.
When a seedling grows too big for its pot, it needs to be moved into a bigger pot in order to maintain healthy growth. This is called ‘potting on’. How do you know when a plant is ready to ‘pot on’? A tell tale sign is when you see the roots of the plants beginning to appear through the holes in the bottom of its pot. Move your tomatoes, aubergines and chillies into larger pots filled with good quality multipurpose or potting compost. Mine are already beginning to get quite big…. which is good as long as I can find space to accommodate them.
Acclimatising plants to the outside
‘Hardening off’ is the term for adapting the plants you’ve started inside to the colder, windier, more fluctuating weather conditions outside. Move your plants outside for a few hours each day on warmer days and remember to bring them in at night. If you need to leave them outside all day while you’re at work, try to provide them with some sort of cover – eg in a mini greenhouse – or, failing that, just put them out on the warmest days (when it’ll be over 10 degrees for tomatoes and not too windy).
Rejuvenating old compost
You can re-use old compost to grow in again this year. The nutrients in the old compost will have been depleted so you’ll need to add some fertiliser, like some worm compost or chicken manure pellets. You can read more about how to re-use compost here.
Start a wormery
If you’re thinking of getting a wormery, spring is one of the best times to do this. It takes time to get a new wormery established. If you start one now, you’ll get lots of wonderful worm compost in time for next year. You can buy a wormery or it’s easy to make your own, here’s how.