April is the month that outdoors seed sowing (both vegetable and flower) starts in earnest. Exactly when in April to start sowing is, however, not easy to specify. The most important factor is soil temperature, with all but the hardiest of vegetables (e.g. broad beans) needing a minimum soil temperature of 7ºC to germinate. A good guide is the rate at which weed seeds are germinating on your prepared beds. There will come a point – typically in the first week of April on the sandy soils of Leith, but in late March during a mild Winter – when weeds of all different types start sprouting up everywhere. This is the time to start sowing. (And weeding!)
Vegetables – Successional Sowing Outdoors
With the soil warm enough, a huge range of vegetables can be sown directly into your prepared beds. Start sowing the following on a successional basis – i.e. small quantities every 2 to 4 weeks to give a steady supply and avoid gluts.
* Herbs: two new varieties of basil I’m keen to try this year are ‘British’, developed specially for our climate, and ‘Summer Surprise’, a purple variety with good vigour and response to cropping.
Vegetables – Maincrop, Outdoors
With these you sow/plant all that you’ll need for the year in one go. Again, sow/plant only when the soil is ready.
Note that swede, belgian chicory and pak choi are not sown until next month. This is because they have a tendency to bolt (run to seed) if sown too early.
Vegetables – Indoor Sowing
Florence fennel, celeriac and celery, although hardy plants, need a warmer soil to germinate. Hence, they are sown indoors, at a temperature of around 10-15ºC, and planted out next month.
The following need to be sown indoors because they are half-hardy and so cannot survive frost. They are planted out next month, after the last anticipated frost.
- Squash and pumpkin
- Outdoor tomato, cucumber and aubergine
- Sweetcorn (choosing a variety suitable for a northern climate)
- French beans
- Runner beans
Squash: If you’re thinking of trying butternut squash, try ‘Harrier’ or ‘Hunter’. Both these varieties do well in our climate.
Cucumbers: there are a number of new, often small sized, varieties that are a great improvement on the old outdoor varieties. Eg ‘Rocky F1’ ‘Beth Alpha’ and ‘La Diva’ (all smooth with good taste and texture).
Sweetcorn: Personally, i’ve found ‘Swift F1’ and ‘Sundance F1’ to do well in a typical Edinburh summer. If you have the greenhouse space then you could go for one of the supersweet varieties such as ‘Lark F1’ and ‘Prelude F1’
French beans: Try ‘Castandel’ – compact but high cropping
When the soil is ready for seed sowing it is also ready for potato planting, both early and maincrop varieties. Plant in rows 2ft apart, 1st early varieties spaced 12” apart, 2nd early and maincrop varieties spaced 18” apart. Planting depth is around 6”. Potatoes like a moisture retentive soil, so plant in a bed prepared with a good amount of organic matter.
If you need any further advice about what to grow and how do grow it, or if there’s anything above that needs further explanation, then please feel free to contact me at: firstname.lastname@example.org