Sowing Vegetables Early – When to Sow?

The following is an extract from How to Create a New Vegetable Garden by Charles Dowding.

How early can you start sowing? I think we all have itchy fingers in the late winter and spring, keen to see those first seedlings pop up and say hello to spring. But when I look back on my earlier-than-usual sowings of the past 30 years, very few succeeded. And I lost a lot of seeds. Here are two tips. First, know the best time for first sowings of each vegetable. Second, follow the advice in this chapter on ways to succeed with early sowing. Some vegetables give their best harvest from a spring sowing, but others do not, and need sowing in summer. In general, the summer solstice marks the boundary between these two groups. This chapter deals with vegetables in the first group, as well as those few that can be sown both in spring and after midsummer. For extra clarity, vegetables covered in this spring-sowings chapter are divided into two types, according to how much they need extra warmth for germination and early growth (see Chapter 9 for more on this).

All the vegetables that are best sown in summer are covered in the next chapter. Their best sowing times are generally after the solstice, to avoid the spring flowering season of these plants. I suggest you buy their seeds in winter or spring to have them ready for summer sowing, helping to keep the ground full all year, giving food most of the time.

Knowing the right time to sow

A good starting point is to keep within the broad time ranges given in the table on page 154 (at the end of this page). It lists the main vegetables for spring sowing, 2 months earlier indoors than outside, when you have an indoor space for sowing.

In spring, wait to sow; in summer, sow on time
Be wary of advice on seed packets which encourages sowing early, even in milder areas. ‘Sow carrots in January and you’ll never have to eat carrots’, as the saying goes. Some seeds, such as carrot, lettuce and beetroot can germinate in cool soil but rarely thrive when attempting to grow in still-cool conditions. Often they are eaten by slugs, buffeted by wind and grow into poor plants.

Throughout spring, the days grow longer and the chance of warmth increases all the time. Using fleece can help early sowings of cool-start vegetables, but not heat demanding seeds such as French beans, runner beans and sweetcorn: for these, you just need to be patient. If you miss a chance to sow, there will be others.

In summer the opposite is true, because days shorten after the solstice and temperatures drop quickly as summer changes to autumn, so later sowings are at risk of running out of time. Sowing dates in summer are therefore more precise, and by late summer there may be just 1 week of good time to sow certain seeds, after which it is too late. See Chapter 11 for key dates.

Tips for first sowings

Gardening is an exercise in optimism, and to some extent a gamble too, in view of the unknowable weather to come. So – again – don’t sow too early in the spring: this way you will reduce potential losses of seeds, plants and time. This advice is hardest to follow in a mild winter and early spring, and occasionally it can be worth sowing earlier than usual, but on the whole, patience pays off.

You just need to ignore those allotment or garden neighbours who brag about having already sown this or that. In spring, later sowings often catch up with early ones, to grow larger and more healthily in the end. See what the neighbours think then!

Spring weather is hugely variable

The effects of weather are often underrated or not explained enough in advice on gardening. For example, in my first year at Homeacres, the cold spring meant waiting a whole month later than usual before sowing outdoors. Sowing dates in spring are a guide only, and if the weather is too cold or wet, you need to wait. In cold weather, raising plants under cover for planting out is more feasible than sowing direct (see below). So:
– Do not sow before the recommended dates.
– If weather is colder than usual, wait until it improves.
Sowings made under cover cope more easily with low temperatures, since they are protected from wind and rain. In early spring they grow slowly but surely, until needing to go out when their roots have filled the modules or pots. Even if the weather is unfavourable, you can plant out and then cover over with fleece.

Using fleece, cloches and minimal hardening off

Fleece covers are easy to use and protect plants from cold wind. The first day of April 2013 in south-west England was a great example of this, with some plants ready to go out but the temperature only just above freezing, at 2 Degrees Celsius (36 F), and the wind making it feel even colder.

I brought module trays of lettuce, spinach and onion straight from the unheated greenhouse and we put them into beds without hardening them off. This is possible in spring for four reasons:
– In an unheated structure, nights are cold and plants are used to low temperatures.
– With protection from fleece, plants quickly recover from the brief shock of going into cold soil.
– Fleece creates favourable conditions after planting, in terms of the temperature of both air and soil, ad wind protection, which are significantly more useful than any pre-warming of the soil.
– Rapidly increasing levels of sunshine ensure enough growing time each day for plants to establish well.
I dibbed holes, Steph planted the seedlings, and then we rolled out fleece on top of them, flat over the beds with the cover resting on top of the plants.

The weather continued frosty for another week and with plenty of cold winds all month, but the only damage to these young plants was from leatherjackets eating some roots (see Chapter 3, page 53).

Tip: How to use fleece. Laying fleece on plants, rather than supporting it with hoops, keeps any warmth closer to the plants’ leaves and roots. It also results in less damage to the fleece, as it is held more securely in place, tight over the bed and firmly on plants’ leaves.

Sowing and planting dates

The sowing, planting and harvest dates for the vegetables described in this section are summarized in the table overleaf, where they are listed in a suggested order of first sowing date. The date ranges given there, and in the table on page 162, are suitable for most of the UK, equivalent in climate to US plant hardiness zones 8-9 – adjust them accordingly if the climate where you live is different. The ranges indicate the earliest possible sowing times, and options to sow later where this is possible.

The ‘first harvest’ dates in the table give an idea of the likely time for first harvest, based on the dates of first sowing.

We hope you have enjoyed this extract. For more information on the book and purchase links you can find it on our website.

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