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Gardening Tips - Growing Spinach

Billy Clifford advises on cultivating spinach.

I'm talking a true spinach, (Spinacia oleracea) as opposed to the spinach beet which is normally grown by organic growers. Spinach beet is not really a spinach at all and despite its ease of cultivation is greatly inferior in flavour to the true spinach. The reason for the popularity of spinach beet is the fact that it doesn't require the successional sowings necessary to keep up a supply of true spinach - one sowing lasts a full season. However, its popularity as a salad leaf encouraged me to take another look at the "real thing" as an intensive crop. The response from chefs was encouraging and there is a good demand for spinach both as a salad leaf and in gourmet dishes right the year round. You can grow it all year round by using a polytunnel during the winter months. Spinach is, in fact, a cool weather crop and supply can be more difficult to keep up during the warmer summer months.

Sowing

It can be grown both as a direct seed or a transplanted crop. I favour a seeded crop but a transplanted crop can be useful if soil conditions don't allow for easy seeding or whilst waiting for tunnel space to come vacant. Blocks or plugs should be seeded with up to five seeds and transplanted at about three weeks old. Germination in a tunnel will only take a few days and it's essential not to allow the blocks to dry out. One slip-up at this stage and you may as well scrap the lot as the crop will probably bolt prematurely. In fact herein lies the main problem with spinach growing: it runs to seed very quickly given any set-back. This is another reason why a lot of growers tend to avoid the crop.

The blocks or plugs can be set out six inches apart in rows twelve inches apart. I prefer to seed directly using a hand pushed seeder fitted with the proper spinach plate. I have also seeded the crop using the plates recommended for beets and chard, which puts out a lot of seed and gives a very thick stand - it's up to the individual grower to decide what suits him or her best. I suspect that the heavier seeded crop might be quicker to bolt in high summer but I haven't been growing it long enough to be certain.

Soil fertility

One thing is for sure, the crop requires the best of growing conditions. A highly fertile soil is required, so incorporate plenty of well-finished compost and ensure the crop always has adequate water. Spinach likes a pH of between 6 and 7.5, so lime if necessary. A heavy clay-type soil suits it better than a sandy soil and you could choose a shaded spot that retains moisture better. On a sandy soil lots of organic matter will be required. Where small but frequent sowings are made this is not too difficult. The rows can be seeded quite close together with just about six inches between to allow for hoeing. Several rows could be grown together with a wider pathway every so often from which to carry out cultivation and harvesting. Keep the crop weed free or this will be a big problem at harvesting.

Continuous cropping

How often one sows depends on a lot of factors- soil type and fertility, season and so on. As soon as the leaves reach the size of a one-pound coin I would sow again, but less frequently in winter as the crop lasts much longer. I'm working on a planting chart for a full season. Last season I made two sowings for the winter crop, one in late August and the other in late October. Both are still cropping well towards the end of March and I am well pleased as there is not much left at this time of year. I think as space becomes vacant in tunnels, spinach could be drilled at any time during the winter months, however do avoid seeding during very cold spells.

I harvest by cutting the plants with a scissors and wash them in a basket for bagging. This keeps the humidity up which prevents the leaves from wilting. For salads the plants are cut when small and bagged in IOFGA lettuce bags. More mature leaves are put in the larger potato bags - one pound in each bag. If the leaves become too big for salads they can be used for cooking. As soon as the crop starts to seed, pull it up and start on a new lot.

Price

If it is to pay well, you will need to get a premium over the price paid for spinach beet. This is to cover the extra labour and attention to detail required to grow a good crop. At the moment we charge £2.50 for salad leaves and £1.20 per pound for mature spinach. As for varieties, the choice is wide. I have grown Matador organic from Kings Crown and this year I'm growing Grodane F1. Apart from slugs, which must be regularly controlled, spinach is pretty trouble free. If well fed and organically grown, diseases should not be a problem.