September in the Vegetable Garden
Following our article on Autumn sowing for the polytunnel (17th August), we have had a number of requests for information on outdoor sowing in September, naturally I am happy to oblige.
One of the reasons I am so happy is it will be a very short article as there is very little you can sow. Early September can be deceptive as seeds will germinate easily (in relatively warm weather) but they won’t have enough time to reach maturity before it gets too cold for growth, usually by early November. I don’t want to state the obvious but as we move towards the 21st of December, temperatures are dropping, days are getting shorter and light intensity is diminishing. No matter how optimistic we want to be, this is happening and it is happening fast.
Of course, this doesn’t mean the garden year is over. September and October are very busy months for harvesting; the image above was taken in early October last year and shows curly Kale which will keep going all winter and carrots over the other side of the garden, there will have been plenty more elsewhere in the garden including Brussels sprouts, celeriac, winter cabbage, leeks, oriental salads and parsnips.
We also need to be aware that, like many things in life, gardening is a cycle so technically there is no end to the gardening year. As I think I said in last week’s mail, apart from harvesting, the most important job at this time of year is feeding and protecting your soil for the winter. Soil building work done now will pay for itself many times over next season with larger, stronger growing crops that grow with less inputs required from you. Remember that plants have immune systems just like us; a vigourous, healthy plant fed by a diverse nutrient rich soil (a balanced diet) is far better equipped to fight than a weaker plant fed on directly applied fertilizer (junk food).
I will expand on soil building in a minute but first I better answer the original question on sowing seeds:
While it is tempting to take a more optimistic tone here (we sell seeds after all), I can only advise a small range of fast growing crops for September sowing including Oriental salad crops, turnip (for turnip tops rather than roots), lettuce (preferably winter varieties) and Summer or Winter radish. Obviously the earlier in the month you sow, the better. As per my previous mail, if you have a greenhouse or polytunnel you will have a much expanded list of options.
On a positive, there are a very wide range of Oriental salads with a huge variety of leaf shapes, textures and colours. Flavour ranges from fresh, crispy and mild (Mizuna) to hot and peppery (Rocket, Osaka, and leaf mustard). My personal favourite is leaf mustard (pictured above), either red or green frills varieties, they have the peppery punch of rocket but a much broader all round flavour.
Turnip tops (above) are the leafy part of the turnip and can provide a number of harvests of (also peppery) leaves in autumn and early winter before they eventually run to seed. The seed heads are a treat in themselves, known as ‘cime di rapa’ in Italy (traditionally served steamed with olive oil and garlic), they have recently became very fashionable in top restaurants so another one worth giving a go. You can buy specific cime di rapa seed varieties but any maincrop turnip seeds will do almost as well.
Overwintering Onions & Garlic
Overwintering onions can be planted in September and October and will produce onions 6-8 weeks before spring planted sets are ready in July and August. Autumn garlic can be planted from September to November. Autumn garlic will yield a better size clove than spring garlic but is not advisable in a wet garden. If you live in a wet area plant autumn garlic in a raised bed or wait until early spring and plant spring garlic.
If you have any beds which won’t be filled with another vegetable crop this season they should be covered either with compost or a green manure crop to prevent nutrients being washed out over the winter. Green manures have a range of benefits depending on what you sow but, at this time of year, their chief purpose is protection. The foliage of a crop like field beans (a close relative of broad beans) helps protect the soil from harsh weather while also preserving nutrients by storing them in roots and leaves that can be cut and composted the following year.
Like all members of the legume family, field beans have the ability to process atmospheric nitrogen and store it in nodules in their roots. The photo above shows the roots of broad beans I grew this year; the white lumps are the nodules which are grown by the beans to house bacteria that do the nitrogen processing for them. One of the benefits of growing a field bean green manure crop is that the nitrogen rich roots can be left in the ground to help feed the following crop. In my opinion this benefit has a tendency to be overplayed but it is a benefit nonetheless.
Make sure to check the recommended sowing date for any green manure you buy as there is a perception that they are all sown in Autumn but this is not the case. Of the varieties that we stock, the field beans mentioned above will be the most suitable for a September sowing. If you would like more information on green manures, I include a link to our blog below.
What are Green Manures?
Feeding and Protecting Soil
Looking after your soil is the key to becoming an ace grower, there is no other secret. Healthy soil is bursting with life (a single teaspoon holds over a billion bacteria) which process organic matter (anything that was once alive) and transforms it into food for your plants. David Attenborough said in his recent documentary “look after nature and nature will look after you”, the same applies in your garden – look after your soil and your soil will look after your plants (which in turn will look after you).
You can build up and feed your soil by adding organic matter in the form of manure, garden compost, seaweed or leaf mould to the surface and letting it rot down over the winter. Feeding mulches also help protect the soil from heavy rain and prevent nutrients from being washed out as well as covering weed seeds and preventing them from germinating.
Autumn/Winter Soil Feed Products
I understand that I am lucky to be able to get my hands on organic manure and seaweed and that most gardeners don’t have that luxury. We are able to supply organic compost (which includes manure) as well as seaweed meal which, although it doesn’t have the bulk of fresh seaweed, will do the same job.
Covering with Mypex or Black Plastic
Although the nutrients contained in organic matter are far less soluble than chemical fertilisers, they will break down over time and can also be washed out of the soil. If, like me, you live in an area of high rainfall I would also advise covering your beds with a black plastic sheet like ‘Mypex’ landscaping fabric to prevent this happening. A good landscape fabric is UV stabilised so won’t leach chemicals into your soil. I understand it might seem odd adding plastic sheets to your garden but it is probably the ‘greener’ thing to do in the long run rather than wasting nutrients and possibly polluting groundwater.
Smashing Pumpkins (and squash)
Let’s finish up with a few photos from the garden and a couple of tips. The thing above is obviously a pumpkin in the process of turning from green to orange. This change started about a week ago and should be complete by mid September, a little earlier than outdoor pumpkins (this one is in the tunnel). Apart from colour (which should be a rich, dark orange), you can tell if a pumpkin is ripe by giving it a thump, if it sounds hollow it is ready to pick. Cut the ‘handle’ at the point it joins the main stem rather than at the fruit end and the pumpkin will keep for longer.
In the same family as pumpkins, this photo is of squash ‘Crown Prince’ or at least a small part of the plant which is currently taking over the polytunnel. The vine originated in the bed in the background but clambered up the tool bench, I didn’t remove it as it had set a cheeky fruit which you see perched on the edge of the bench.
‘Crown Prince’ is a fantastic squash with smooth grey/green skin and contrasting bright orange flesh, it is really beautiful when cut open. For the big fruit pictured, it is best to limit the amount of fruit on the vines, in my case to 5 large squash.
This one is squash ‘Delicata’, also known as sweet potato squash, it is one of the very best for flavour. ‘Delicata’ is a small fruiting variety so you will get more on each vine, I must have 10 or 12 on the go. This variety needs a good summer to ripen which is why I have them growing in the tunnel, if grown outside in a cool year it may be better to limit fruits to 5 or 6 in mid August to give the best chance of ripening.
Saving French Bean Seeds
These pretty little fellas are ‘Borlotto lingua di fuoco’ which are now dry and ready to harvest for winter storage or for seeds for next year. To keep beans for drying, you simply leave them on the vine and harvest when the pods are dry and papery and the beans are rock hard. It can be difficult to dry bean seeds outdoors in a damp climate so I grow them in the tunnel, if growing outside and Autumn doesn’t go your way, pick when yellow and dry indoors otherwise they may rot on the vines.
OK, that’s about it for today, I will see you next week!