Okay here we go: You can’t book a holiday just yet, and lettuce is not just lettuce!
I’ll explain. Many of us gardeners have been harvesting crops in the garden and the polytunnels, enjoying the fruits of our seed-sowing endeavours early in the year. Many of us might even plan a little holiday in the sun if the Irish summer does not improve, but (not only) polytunnel owners be aware there is another important job waiting for you: Sowing for the Autumn and Winter season at the end of July and early August to establish crops for what we call winter harvesting.
Oriental vegetables (as in oriental lettuces) are becoming more and more popular in Ireland. They suit the cooler months of autumn to spring and most of them can be grown fast and intensively, especially when cultivated as ‘cut-and-come-again’ crops.
Winter salads, endives and orientals
There are plenty of different salad varieties which can be sown now, for example winter lettuce like Bartima, Brighton and Brune D’Hiver. We suggest sowing them in modular trays (one seed per cell) and planting out in the polytunnel when the seedlings have developed a strong root ball.
There are also different varieties of endives available. Endives are hardy, have a distinctive slightly bitter taste and are rich in minerals and vitamins. They can be sown from now until December-the same way as winter lettuce.
Oriental greens like Mizuna, Pak Choi, Tat Soi and Salad Rocket are quick-growing winter salad crops. They perform best, if they are raised in modular trays. (Three to five seeds can be sown in each cell of the tray). After three weeks, the plants are ready for planting out and after another two to three weeks they will be ready for harvesting.
Lamb’s lettuce is another excellent-tasting winter lettuce that can be sown in September in modular trays or directly. The small rosettes can unfortunately only be cut once, but their lovely flavour makes growing them worthwhile.
Winter Purslane or Claytonia are also easy to grow. The vigorous plants can be cut several times through their growing season. In early spring Purslane will develop white little flowers-these are edible and looking nice on the plate.
At The Organic Centre we sow our oriental brassicas twice a year, in spring and winter. The plants sown from February to April will be harvested at the end of May whereas the plants sown from August to September will be harvested at the spring of the next year.
Some Orientals can be grown in the outside garden, but we grow them in the polytunnels because they are cleaner with less dirt and moisture problems.
Due to the lower light levels and temperatures in autumn and winter growth will be much slower from September onwards. A heated bench in a glasshouse or a small propagation unit would be a great advantage, increasing the chances of strong and healthy seedlings. Lettuce germinates best at soil temperatures between 15-18ºC. All the other crops mentioned above have an optimum germination temperature of 20ºC. Growing the seedlings on a heating mat will speed up the germination process to five to seven days and will give the plants a good start.
The seedlings will grow without the extra heat, just much more slowly. For all the over wintering polytunnel crops, good ventilation and drainage are necessary to avoid the development of fungal diseases.
If you only grow a few of the crops mentioned above in your polytunnel, you will have a fantastic variety of fresh greens, rich in vitamins and minerals for your salad bowl in winter and early spring. Try it. Good luck … and have a nice holiday!
Hans Wieland is training manager at The Organic Centre, Rossinver, Co Leitrim, which offers courses, training and information on organic growing and cooking, and runs an Eco Shop and an online gardening store. For more information, visit www.theorganiccentre.ie.
Gardening questions or comments? Contact Hans at firstname.lastname@example.org.