Winter Garden Gets Its Blanket

We are having a White Christmas here in Seattle, with a gift to my garden (and me) of a nice blanket of sparkling snow.

Here are images from my garden today.

Merry Christmas!

yard

A Christmas view of our yard from the house.

brroccoli

Broccoli shoots peek out of the snow cover.

cloches

Glass cloches protect young plants from the snow.

cold frames

A plastic cloche covers lettuce, and a double window A-frame covers overwintering beets.

cold frame closer

The beets are tiny and might handle this cold, but I should have put ends on this double-window cold frame for better protection.

big bottle cloche

A big water bottle protects a young cabbage.

yard with cold frames

Cold frames in the background protect greens, but lots of brassicas fend for themselves under the snow.

Cold frames

The big cold frame in the back and the smaller Triangle Tunnel in the front both contain salad greens. I won’t open them until our warmer weather returns, but the tender greens should be fine. Snow is a great insulator!

dino kale

Dinosaur kale is tough!

parsnip

A Christmas stew is going to contain fresh parsnips, pulled today from the snowy ground.

Why Broccoli Didn’t Flower

Recently, a gardener asked our Master Gardener clinic why their broccoli didn’t flower. That question comes up regularly, and I’ve studied it in my own garden, with my own successes and failures.

Someone also asked me the other day if it was too late to plant winter brassicas.

Finally, I want to share a tip about what to do with your Brussels sprouts plants this time of year.

So I’ll tackle three brassica topics in this post. Here we go.

Why broccoli didn’t flower

If your spring- or summer-planted broccoli didn’t set its flower buds (the part we eat), it could be due to  planting at the wrong time, uneven watering, fertilization issues, planting bad starts or bad treatment of seeds or seedlings.

For summer harvest broccoli, timing is tricky, because you want to plant earlier in spring so you get the crop before the summer heat, but if you plant too early, the broccoli won’t get a robust start. If you plant too late, the heat stresses it. I’ve had best success when planting starts in early to mid-May (or doing a succession of plantings through May). That means you’ll be cutting heads in mid-July and into August.

In my experience, they like a lot of compost, which also helps to regulate moisture. So I put them in a well-composted bed, and add a top-dressing a few weeks after planting. I’ll feed once with a balanced complete organic fertilizer, about a month after planting.

Fertilizing with a lot of nitrogen as they’re trying to form heads could prevent the plant from flowering, and probably just produce more leaves.

For overwintering broccoli like purple sprouting (my favorite), I start the seeds in late May/early June, then plant them out in August. Also tricky to keep them consistently watered during that seedling stage. I top-dress with compost in mid-September, then lay a bed of straw mulch over the soil for the winter. They’ll send up a small central head by early March, followed by sprouts.

I don’t grow fall-harvest broccoli often, but I believe that it’s on the same planting and transplanting schedule as sprouting broccoli, but will produce heads in late September. I found the harvest to be small, so now I just concentrate on the sprouting ones.

Brussels sprouts ‘tip’

On to the Brussels sprouts. If you have winter harvest sprouts in the garden now, you’ve probably noticed small sprouts forming along the leaf axils. Also, you’ll probably see a denser set of leaves forming like at the top of the plant. If you cut off that growing tip, the sprouts should develop faster and more robustly. That’s because the plant is now putting all its energy into the sprouts rather than the new leaves.

Here are photos showing this cut on one of my plants:

Brussels sprout topBrussels sprout top cut

Planting brassicas now?

One final note about whether you could be planting brassicas now. The answer is, not really.Most brassicas should be planted in May and June, and transplanted in August, or at the latest in early September.

However! If you can find healthy kale plants still in the nurseries, you could put them in, but I would not expect much production from them over the fall and winter.

What to Plant Now for Winter Harvest

It may seem crazy, but just as your cherry tomatoes are forming, it’s time to think about winter. seedlngs un traysBut consider the stars of our winter garden: long-season broccoli, cabbage and Brussel’s sprouts. In order to get the sprouts bulging, the cabbage head firming up and the broccoli sending out its shoots, you need to grow a plant that is fairly mature before the onset of winter.  That means starting soon.

The main challenge to winter gardening in the height of summer is water. These cool-season stars need to be grown through our warmest months, and they still might be seedlings when a hot spell hits. So, a cool-season gardener must keep the warm-season vacations short.

Here are a few techniques to make this challenge a bit easier to bear:

Start in flats. Rather than sowing directly into the garden bed, sow into pots and plan to transplant. That way you can keep a closer eye on the moisture content of the soil while the seeds are sprouting — a crucial moment.

Another bonus: the plants will be mobile. You can move them to the shade if you need to be gone for an extended period during a sunny period. Better yet, if you’re planning a weekend away, deliver the tray to a neighbor who can keep an eye on them for you.

Plants you start in pots now would be ready for transplanting near the end of July.

Cover them for shade. Floating row cover, the thin, spun-bonded fabric that lets light and water through, serves in summer as an excellent shade cloth. Drape it lightly over the plants and hold down the edges with earth staples or stones as weights.

An extra benefit of this technique is that the FRC will prevent pests from messing with your plants. The cabbage moth cannot land on leaves that have been covered, so it won’t be laying its eggs, which hatch into voracious larvae.

One caution, though: don’t expect the material to solve all your woes. Slugs and snails will still be looking for your tender seedlings, so patrol the area regularly until the plants are big enough to withstand such an assault. FRC will help the soil retain moisture, too, but again, don’t expect it to do all the work. Check regularly under the fabric to see that the plants are staying well-watered.

Use plenty of compost for moisture retention and a bit of fertilization. Digging in some compost before planting will improve the tilth of the soil, and top-dressing with it after the plants have put on some good leaf growth will provide an additional layer of moisture-holding capacity.

Be aware, though, that top-dressing (spreading a modest layer of material on the surface of the soil around the plant) can get crusty in summer application, which would cause water to run off rather than soak in. Cultivate it lightly before watering if it seems to be crusting over; this will allow the water to get through.

Other things to plant now: parsnips, carrots, beets, chard, kohlrabi, collards…an amazing array of choices for fall and winter eating.

Soon it will be time to start a second or third planting of short-season crops, like lettuce and peas,  for fall harvest. But for now, as you pinch tomato suckers and anticipate the first blush from a chorus line of cheery cherries, think a bit further ahead, to the tasty cool-season crops you’ll want to put on your holiday dinner table.