There is a moment in an Irish garden, usually the first week of September, when the beans come out and the bed underneath them is bare. Most people look at that bare soil, decide the year is over, and leave it until March.
That is six months of empty ground. It is also, quietly, the most avoidable mistake in the Irish growing calendar, because the soil in September is still warm from August and warm soil is what seed actually needs. Air temperature is falling. Soil temperature is not, or at least not yet. You have roughly three weeks of that head start, and four crops that can use it.
Why September sowing works here and does not work in a hotter country
Ireland has a slow, mild, drawn out autumn. That is a problem for tomatoes and a gift for leaves. In a Mediterranean climate a September sowing runs into a hard cold snap and stops. Here the temperature slides down gently over ten or twelve weeks, which is exactly the pace at which a spinach or a chard plant likes to build itself.
The trade off is light, not cold. After the equinox the day length drops fast, and growth slows with it. So the rule for September is simple: sow things that are useful small. A spinach leaf at eight centimetres is dinner. A tomato at eight centimetres is nothing.
1. Winter spinach: the one to sow first
If you sow one thing this month, sow spinach. Matador is a large leaved variety that stands through cold and wet rather than collapsing into it, and it is the difference between buying bagged leaves in November and cutting your own.
Sow direct, about two centimetres deep, in rows twenty five centimetres apart, and thin to fifteen centimetres between plants. Sow now and you cut the first leaves in six or seven weeks, then keep cutting through the winter as long as you take the outer leaves and leave the centre alone. In a bad frost the plant looks finished and flat. Leave it. It usually is not.
2. Perpetual spinach chard: the crop that outlives the winter
Swiss chard Costa Verde is sold as perpetual spinach for a reason. It is the most forgiving leaf in an Irish garden: it stands frost, it stands wind, it stands neglect, and a September sowing will still be feeding you next April. It is one of the few things you plant once and harvest across two calendar years.
Same sowing depth as spinach, but give it more room, about thirty centimetres, because the plants get big. If you only have space for one autumn crop and you want the longest possible return on the seed, this is it.
3. Rocket: six weeks from seed to salad
Cultivated rocket is the fast one. It germinates in a few days while the soil is still warm, it is ready to cut in around six weeks, and it is far better in autumn than in summer because it does not bolt and turn savage when the heat goes. Autumn rocket is milder, broader in the leaf, and it keeps producing after cutting.
Sow it thickly in a short row and treat it as cut and come again. It is also the best crop for a container by the back door, which matters in September when nobody wants to walk to the end of a wet garden.
4. Turnip: the catch crop most people forget
Purple Top Milan is quick, and quick is the whole point in September. It sizes up in six to eight weeks, so a sowing in the first week of the month gives you roots by late October, and if the roots stay small you eat the tops as greens instead. Either way the bed is not empty and the soil is not sitting bare in the rain losing structure.
The two things that will actually cost you the crop
Slugs, first. Every young autumn seedling is soft, wet and alone in a garden where everything else is finished, so it gets found. Protect the rows for the first three weeks, however you normally handle slugs, and after that the plants are tough enough to take the damage.
Timing, second. The window closes around the third week of September, not because of frost but because of light. A seed sown on the twenty fifth of September germinates and then sits there, too small to be useful, waiting for February. Sow in the first fortnight and the plant is established before the light goes.
Two crops that are not part of this
Cavolo nero and radicchio both belong in an Irish autumn, but neither is a September sowing. If they are already in the ground you are about to have the best of them, because both improve after the first frost. If they are not, note them for next year: cavolo nero from February to July, radicchio in August.
What to do this weekend
Pull the beans, pull the courgettes when they stop setting, and do not dig the bed over. Rake it level, sow one row of spinach and one of chard, and put the rocket in a container where you can reach it in the rain.
Twenty minutes of work in the first week of September is the difference between a garden that feeds you until Christmas and a garden that stops in August.
If you want the winter leaves in one go, the Winter Kitchen Garden bundle puts them together and works out cheaper than the packets bought separately. All seed is posted from Co. Longford. BloomySeeds is an Irish stockist of Franchi Sementi seed.
