December 2024 Part II: Seeds to sow in Feb/March for first crops
21st December 2024
I have put this factsheet together, a little earlier than usual, to have it ready for the Christmas period. This leaves room for me to fit in, (January) a short factsheet on growing dahlias, by request.
Two Crops per Season
For optimum use of vegetable beds, it is possible to grow two crops per season from many of your polytunnel and outside beds. This is relatively easy down south with their warmer temperatures and better light levels but up here, in God’s Own County with our shorter growing season, we need to be a little inventive, but it is quite possible.
Basically all vegetables and fruit fall into one of four seasonal categories:-
a. Perennials, e.g. berries, asparagus, rhubarb, artichokes etc
b. All season crops which are in growth throughout the summer period, e.g. parsnips, purple sprouting broccoli, celeriac, celery, main crop potatoes, etc.
c. Varieties of vegetables which are bred for early sowing.
d. Varieties of vegetables that are bred for late sowing.
It is essential to select varieties bred for either early or late sowing (c and d). See my list below. Another advantage of sowing early and late is that the plants then miss their main flowering season, i.e. early crops mature before then and late crops reach the flowering stage after it. This is particularly helpful with plants prone to ‘bolt’ such as Florence Fennel.
To grow two crops per season up here we need to be quick off the mark with sowing. I sow seeds of early croppers in modules as soon as is practical depending on the vegetable. The modules are then placed indoors in a warm place to germinate. But, as soon as they show signs of germination the modules must be placed somewhere a little cooler but with good light but not a south facing position and not outside yet. If the available light is not coming from all four sides and the roof, as is likely in your home, I find a west facing windowsill useful. I turn the trays round 180* each day to help the seedlings grow straight.
I have also made a simple windowsill lightbox by cutting a cardboard box to provide a base which sits on the windowsill and a backing, covered in tin foil, to reflect the light from the window onto the rear of the plants. Works very well for me.
After a few weeks I place the seedlings in a cooler place still, but with good light. This may be in my cold greenhouse with a fleece over them when cold nights are forecast.
A couple of weeks later I start to harden them off by placing the trays on a bench outside the greenhouse during the day or, if this is not practical, fully ventilating the greenhouse in the daytime and closing at night. But often one must settle for ‘best situation available’ due to practicalities.
At some point in this process, you may need to pot the seedlings on into a small pot, then larger pots, until it is safe to plant them into the beds with protection. I ensure the plants have a well-established root system before planting them out.
I also grow some vegetables in good sized pots from February. I fill the pot with multipurpose compost riddled with a 6mm sieve (not seed compost as the subsequent plants will be spending all their life in the pot), sow the seed thinly, cover lightly, place in a warm place to germinate the can be moved to a cooler place but still indoors, putting in the greenhouse well established in March/April. I use this method for early carrots, radish, spring onions and lettuce. In my experience almost any veg can be grown in a container. In addition to pots, I use washing up bowls, (my favourite container), domestic water tanks, crates, buckets, troughs and so on.
My favourite container planting in February/March is a deep trough filled with good quality compost. For containers I use a mix of 2/3rds multipurpose and 1/3rd John Innes No 2 or 3 with the top 2” sieved. I then sow one row each of four vegetables: spring onions, rocket, ‘cut & come again’ lettuce and beetroot. I put the container in the greenhouse or polytunnel with a fleece over at least until growth established.
But remember multi-sown plants in containers need frequent watering and feeding later on.. Remember to drill good sized holes in the bottom of them.
Did You Know?
You can grow parsnips in containers. Parsnip seeds stay viable for only 1 year so after sowing in March/April set the surplus seeds on one side (preferably in a fridge) until September. Then sow them in a deepish pot, leave the pot outside until early winter then take into greenhouse/polytunnel where it stays until baby parsnips are ready in Spring.
Autumn sown seeds
Many early vegetables can be sown the previous autumn, e.g. onions, shallots, broad beans, covered with fleece or mesh. In my polytunnel at the moment I have spring cabbage, lettuce, rocket, beetroot, spring onions, lettuce, broad beans, daffodils in pots and garlic, all growing away nicely, albeit slowly, but will provide some useful veg in late Winter.
They will be followed by tomatoes, cucumbers, melons and more broad beans, courgettes, French beans lettuce and beetroot.
When planted in the beds I put slug deterrents in place, cover the beds with fleece or mesh to protect them, initially from the cold winds and later from pests.
Potatoes, 1st and 2nd earlies are also classed as early season crops.
Meanwhile I give some thought to the late season crops to follow on from all of the above, judging when to sow them to have them ready for transplanting into the beds as soon as they become vacant, or even earlier. By earlier than vacant I mean intercropping.
2nd Crops : Intercropping
It isn’t always possible to wait until the 1st crop has been fully harvested before planting the 2nd crop. When harvesting say early carrots or beetroot rather than harvest by working your way along a row, I harvest at intervals and plant the 2ndcrop plants into these gaps so that at some point there is a bed of maturing beetroots interspersed with young say, Florence Fennel.
With beetroot this method is made easier if you Multisow ( sow several seeds in each cell of a module tray, (3-4 beetroot seeds per cell) as the spacings between the clumps leave a good space for a 2nd crop when I harvest a clump of beetroot. I find other veg suitable for multi sowing are spring onions (8-10 seeds), onions (4-5 seeds) and turnips 3-5 seeds).
2nd Crops : Varieties to use
Vegetable plants I use for ‘doubling up’ are:
(My favourite varieties, following many years of trialling, are in brackets)
1st earlies (‘Winston’) & 2nd early (‘Kestrel’) potatoes
followed by leeks (‘Porbella’) – rust resistant and/or maincrop carrot (‘Berlicum’)
Shallots, (‘Yellow Moon’ autumn sown) followed by beetroot (‘Pablo’)
Onions sets (‘Hercules’) followed by late peas (‘Terrain’)
Early peas, (‘Meteor’) followed by autumn/winter cabbage (any Savoy)
Broad beans,(‘Super Aquadulce’) followed by Purple sprouting broccoli (‘Claret’)
Early beetroot (‘Pablo’) and lettuce (‘Red Grenoble’) followed by Florence Fennel (‘Di Firenze’)and turnips (‘Milan Purple’)
Early carrots (‘Early Nantes’) and Early Florence fennel (‘Di Firenze’), followed by lettuce and celery (‘Victoria’)
Spring cabbage, (‘Wheelers Imperial’) followed by swede (‘Marian’)
There are other ways of doubling up, e.g. intercropping rows, which is planting fast maturing plants/seeds in the spaces between slower maturing vegetables. For example there is a wide spacing between brassica plant rows so sow radish seeds, lettuce plants, spring onions, baby beetroot and turnip seeds in between the rows of brassicas. These plants will mature and be out of the way by the time the brassicas grow sufficiently to need the space. This is a more efficient practise than setting brassica plants out too close to try and save space.
There are other ways of getting two crops per bed, put your thinking cap on when next you visit your allotment or garden veg patch and see what opportunities you can devise that suit your plot.
Another consideration when choosing varieties is disease control.
If your leeks are always plagued by ‘Rust’ disease then choose one of several rust resistant varieties.
If you plot is plagued by brassica Clubroot, again choose a resistant variety.
More on what practises I employ to cope with pests and diseases in a later Factsheet.
In late winter/early spring I also sow a couple of varieties of French Marigold:
‘Double Brocade Red’ and ‘Marietta’, again indoors to germinate them as at the beginning of this Factsheet.
I pot the Marigold seedlings on into progressively larger pots, (6 of them into 3 litre pots for the greenhouse). Been doing this for many years now and can honestly say I just do not get any whitefly or greenfly in my greenhouse. In May I plant marigolds around my allotment close to vulnerable plants, e.g. Sweet Peas and Tomatoes. Well worth doing but doesn’t work quite as well as in the greenhouse. Probably because the pungent smell given off by the Marigolds, which the aphids can’t abide, will be more concentrated within the confines of the greenhouse.
Other February/March Sowings
February is a good time to sow broad beans in pots and then transplant outside.
Sow sweet peas in rootrainers in a cold frame.
Peppers and aubergines indoors as they require a long growing season.
1st early potatoes in second half of March, will need to protect the top growth from frost.
Shallot and onion sets. I start them off in modules or small pots in the greenhouse and plant out when roots well established.
That’s about it on this subject. I hope all this doesn’t appear daunting because it is quite straightforward in practise, but I strongly recommend you get a pencil and paper out and draw a plan. I couldn’t keep track of the process without my plans, even though I do sometimes reach version 5 before the final masterpiece!
I am happy to receive queries anytime.
Look out for the Dahlia growing factsheet early January.
I hope you all have a very Merry Christmas and a good New Year.
I hope Santa is good to you and you all have a cracking horticultural 2025!
Meanwhile,
Keep Healthy, Keep Smiling, Keep Sowing.
Best Wishes,
Ramon 07594 456292
Plot 21 Silsden Road site