Garden Notes for September 2020.
As John Keats so famously wrote about autumn being the “Season of mists and mellow fruitfulness/ close bosom-friend of the maturing sun”, September sees the time when crops are harvested and stored for the winter months that are to come. Carrots should be lifted and stored before the roots start to split, which they will do very quickly once the heavy autumn rains begin. For the same reason, beetroot are better lifted and stored this month. Looking forward to next year, spring cabbage should be planted now. Remember to firm the soil around each plant after planting. Lettuce can also be sown now in a cold frame, or greenhouse. Varieties to choose include ‘Winter Density’, ‘All the Year Round’ and ‘May Queen’.
Watering plants is always a good topic of discussion. It is either too dry, or it’s too wet. The essential thing is to try to get the right balance. When it is dry the closable leaf pores on plants (technically called ‘stomata’) shut down and slow down the process of photosynthesis. When there is enough water the stomata open, transpiration takes place, allowing the air containing carbon dioxide to go into the plant, which, together with sunlight, powers the reaction of water and carbon dioxide to make the sugars that are the plant’s energy source and building blocks. Watering keeps the stomata open in dry spells. As a rule of thumb one square metre of vegetation draws the equivalent of an inch of rainfall every day. Growth of plants in the summer normally requires additional irrigation. There are now numerous automatic systems that can be put in – especially for containers and hanging baskets.
The start of autumn means that many plants are producing seed heads, which we normally ‘dead head’ to keep the succession of flowers going. With the cost of seed increasing year on year (the average cost is now over £3 per packet, and can be a lot more) it might be worthwhile considering saving some seed head for sowing. Flowers like Sweet William, Love-in-Mist (Nigella), Cosmos, or vegetables like Runner Beans, can be harvested just before the seed-pod has fully dried. Use brown paper bags to hang the seed head upside down and store in a dry place. Remember to label the variety, and then when it is all nice and brown shake out the seed and you have saved yourself pounds for a few minutes work. Unfortunately the lovely hybrids that abound now will not breed true and you will have to rely on the expertise of the professional for that, but if you don’t mind a variety of colour in your Sweet William and so on it is fine. One tip is to look out for Garden Centres having a seed sale, there are bargains to be had, with cuts up to 75%, when they are sufficiently desperate to make room for the new stock.
The growth of rampant climbers like some of the clematis (remember to check) wisteria and climbing roses can be cut back in the middle of September.