Remember, always sow the seeds. You can catch up on everything else, but if you don't sow seeds on time - you may have lost your chance. This is especially important for any late autumn and winter crops that need starting off now!
Ruby chard Vulcan - one of the best winter crops in the polytunnel or outside.
Hearting chicory 'Sugar Loaf' or 'Pain de Sucre' - another winter standby in the polytunnel or outside
*Also very important* - If you haven't got seeds of winter vegetables you will need then get them as soon as possible, as many garden centre shops take their seed displays down this month, and online may also be sold out. Things are calming down a bit on the seed sowing front now - but many crops that need sowing now need sowing as soon as possible, if you want to get decent crops over the winter. With light levels decreasing, growth of many crops slows up dramatically towards the end of this month. After that, only the faster-growing autumn crops will reliably give you a good crop before the winter, and growth of overwintering veg like chicory and chards will also be much poorer. Remember that plant growth is governed by light - not warmth.
Seeds to sow now for late autumn & overwinter protected polytunnel crops:
Sow outdoors in pots or modules, for planting later on in the tunnel or greenhouse when space is freed up and the tunnel or greenhouse is cooler:
Calabrese*, kales such as Cavalo Nero, dwarf green or red curled and Ragged Jack, Florence fennel, beetroot, kohl rabi, Swiss chards**, early peas, dwarf broad beans, Sugar Loaf chicory**, basil, coriander, dill, plain leaved & curly parsley, and sorrel. Covering while outdoors with a fine mesh-covered frame or cloche will give young seedlings protection from pests (like cabbage root fly and cabbage white butterflies), and also from scorching sun, strong winds or heavy rain.
In the polytunnel, if you have any vacant space after clearing early summer crops, you can still sow:
Dwarf and climbing French beans, or early varieties of peas such as Kelvedon Wonder, and fast-growing dwarf broad beans such as Express or The Sutton - to crop in late autumn* (otherwise sow in pots or modules for planting later when space becomes available). Sowing in pots and modules helps to make the most of valuable tunnel space as it means that you can have large plants ready for planting as soon as any early summer crops are cleared.
Seeds to sow outdoors for autumn and overwinter crops:
In modules, in a seedbed for transplanting, or in situ where they are to crop:
Beetroot, brocoletto 'Cima di Rapa', carrots, cabbages ('Greyhound', leafy collards and non-hearting spring types**), overwintering spring-heading cauliflowers**, peas* (early dwarf vars.only now), Florence fennel, 'Witloof' chicory (for winter forcing), sugar loaf chicory, radicchios, endives, salad onions, claytonia, landcress, lettuces (Lattughino, Fristina, Winter Density, Jack Ice, Cherokee, all good varieties), kohl rabi, 'Hungry Gap' kale (for spring cropping), radishes, rocket, Swiss chards and leaf beets, perpetual and summer spinach, summer white or yellow turnips, Chinese cabbage, Choy Sum, Pak choi, mizuna, mustard 'Red Frills' and other oriental leaves, Chinese kale (Kailaan), lamb's lettuce (corn salad), salad mixes, herbs such as parsley, chervil, coriander, dill, fennel, buckler-leaved and French sorrel.
Also sow some single, quick growing, annual flowers such as limnanthes (poached egg flower), calendula, Californian poppies, nasturtiums, phacelia, etc. to attract beneficial insects like hover flies to help with pest control, and bees to help with crop pollination. Sow fast growing green manures like buckwheat, red clover, mustard (which is a brassica so watch rotations) and Phacelia, to improve the soil, 'lock-up' carbon and feed worms (after digging in), on any empty patches of ground cleared of early crops that won't be used for 6 weeks or so, or which needs improving. This is also the best time of year to sow all types of hardy herbaceous perennials, biennials and wildflowers. Foxgloves, primulas and hellebores in particular germinate really quickly and easily if sown as soon as this year's seed is ripe.
Again - sowing into modules means that you will get maximum crops out of your space by always having something ready to plant wherever there is room - bigger module-raised plants are also more resistant to slugs and other pests. Sowing a wildflower meadow mix in seed trays or modules is actually a far more reliable method of establishing a new meadow than trying to sow directly into grass where there is too much competition from other mature plants and also many pests. These can be planted out in patches later.
(*Early July only, ** mid-late July)
N.B. At this time of year, it is best to sow seed modules in the evenings, or in the shadeif possible -
Germination of many seeds can be badly affected or sometimes even completely prevented by very high temperatures - this applies particularly to lettuce and spinach seed which can become dormant if sown at too high a temperature. You don't want to 'cook' your plants until you're ready to eat them!
Once again - don't forget that all growth begins to slow down progressively from the end of July onwards due to the decrease in daylight length. So in order to get a worthwhile, continuous winter harvest of some varieties, you will need at least one and a half times as many plants of leafy crops in particular, than you normally would need for summer crops.
!! A warning - If you are collecting seed from plants. - It's a great time of year for saving all types of seed from your own plants - but be careful! Many kinds of plants - particularly Hellebores and Euphorbias - have irritant toxic sap which can give you very severe and extremely painful burn-like blisters on the ends of your fingers and hands - as I know to my cost! To be on the safe side - always wear gloves when collecting seed from any plant - even if they're not well-known to actually be toxic - you never know what you personally may be allergic to!!