If you haven’t already sown beets, chard and leaf beet, rutabaga, radicchio, kohlrabi for winter harvests, do it right now so that plants have enough time to get to a mature size by the end of October. It is also time to plant out starts of winter broccoli and cauliflower and long-season cabbage (it is too late to sow from seed). If you sow now, you can still get very nice heads of the small pointy ‘sweetheart’ cabbages (Caraflex F1, Early Jersey Wakefield, Greyhound).
For successful winter harvests, plants have to have enough hours of daylight in the growing season to reach a good size because they can’t grow in the winter cold. When the sun is high in the sky at this time of year most gardens have enough daylength for good plant growth, but as the sun gets lower in in August, sunlight is increasingly blocked in the morning and afternoon by buildings, trees, even mountains. If you are gardening in a wide open area without such obstructions, you can plant a couple of weeks later than my suggested planting schedule, because your garden will receive more hours of sun. For the rest of us, planting on the earlier schedule compensates for fewer hours of direct sunshine in late summer and fall.
Carrots: Carrots take the longest to germinate and grow slowly so if you want additional carrots to see you through the winter, sow immediately (this minute!). You can count on carrots to take 6-7 days to emerge; by the time they come up, the bed should be covered with insect netting or floating row cover to keep carrot rust flies from laying eggs on the plants. Most people will be familiar with this common pest, but if you aren’t, here is what the damage from the larvae burrowing in roots looks like: http://www.lindagilkeson.ca/root_feeders.html#67 Even if you usually don’t see carrot rust fly damage in your spring sown carrots, it is still advisable to cover later sown carrots because there are lots more adult rust flies flying around in August and September. If there are rust fly maggots in the roots in the fall, they just keep on feeding through the winter, making more and more of a mess of the roots.
More greens and roots: There is no rush to plant the following, but you might want to plan where you will sow these plants from late July to early August: kales, collards, mizuna, daikon & other winter radishes, broccoli raab/rapini and all kinds of leafy greens (leaf mustard, mustard spinach/Komatsuna, arugula) as well as Chinese cabbage (Joi choi, bok choy, napa cabbage, etc.). For some of these crops you will also be able to buy started plants from nurseries this month and in August. This is the time when I start ‘editing’ the garden to make space for winter crops. I remove surplus plants (zucchini!), that are getting over-mature (why did I think I could eat all that endive?) or that are not doing well (a couple of corn plants are too far behind to catch up…). Such spaces, no matter how small, can all be used to grow something for winter.
Onions: You can experiment with sowing sweet onions, such as Walla Walla, Red Torpedo/Rossa Lunga di Firenze, in late July. If they survive the winter, they produce very early, mild onions next spring. If you live where winter precipitation is usually rain, most of the plants may make it through winter (they are quite hardy), but if you live where it snows occasionally, the small plants should be protected by a plastic tunnel or coldframe to prevent being crushed by the weight of snow.
Spinach: I find the best timing for sowing spinach is early August: by that time the days are short enough that most varieties of spinach won’t flower later this summer. You can harvest spinach from these late sown plants all fall and the same plants will also produce a big crop of leaves in the spring too.
On Salt Spring, Chorus Frog farm stand currently has a variety of starts for winter crops, including kales and other greens, purple sprouting broccoli (in mixed flats of several varieties) and winter cauliflower (Purple Cape, Galleon). If you are buying at garden centres, any variety of kale, spinach or chard available should be fine for winter planting, but beware of the wrong varieties of (summer) broccoli and cauliflowers that are still being sold to the unwary by the ill-informed (are you all sick of my annual rant about this yet?). Speaking of the ill-informed, I mentioned Cardinal Late purple sprouting broccoli in my last email, but it seems that seeds are no longer available (I am still planting from an old packet) so I am sorry to have sent some of you on a wild goose chase. I hoping a local grower will put this variety back into circulation by growing seed for sale.
Whether or not you need to add nutrients before sowing or transplanting this round of winter crops depends on how well the preceding crop grew in that soil. Established gardens, well-fed with compost and a steady supply of organic matter from mulches usually don’t need more amendments in mid-season. If they do, as is often the case in new gardens, it is usually nitrogen that is in short supply. It can be supplied by blood meal, alfalfa meal, fish meal or other nitrogen rich amendments, including fish/wood waste composts (e.g.m SeaSoil, Earthbank, Oly Mountain brands). These supply roughly 2% available nitrogen. Don’t use bone meal or bone/blood meal—most soils already have plenty of phosphorus.Linda Gilkeson