In my Seattle garden, fallen leaves are drifting up around the edges of my vegetable beds like Technicolor waves lapping at the shore. Time to deploy the season extension.
This time of year, nature is getting ready to go dormant. Despite the occasional warm, sunny day, the weather pattern is changing. Shorter days (and longer nights), cooler temperatures, glorious rain, from drizzle to downpour, all signal the change in plants. Growth slows down. Cell walls begin to thicken in the plants, mirroring our defensive layers of fleece and wool.
Stave off the inevitable decline in your vegetable garden by covering those plants that are actively growing. The ones that will feed you salad this fall can be nursed along for a few more weeks if covered with a cloche or a cold frame.
The root crops that are going to be overwintered will be aided by a blanket of garden fleece, also known as floating row cover. Later this fall, you can pull off the FRC and cover those beets and carrots with a cloche, giving them more protection during our coldest time.
The kale, cabbage, broccoli and Brussels sprouts will benefit from a top-dressing of compost and straw mulch, between the rows and around the plants. This step can be taken for all the fall and winter veggie plants, but isn’t as necessary for those under a cloche or cold frame until the weather really reaches our daytime winter temperatures of 45 degrees. Still, I often do this now around my salad greens too, just since I’m out in the garden with the straw at hand. It’s often more pleasant to do it on a nice fall day than try to wait for a break in the winter rains that will take hold in November.
The main reason to do this season extension and mulching work is to protect our plants from the colder temperatures, pounding rains and desiccating wind.
A few weeks ago I put in a late batch of lettuces and raddichio into a long hoop-house cloche. With the unseasonably warm weather, I’ve been able to take that off for days at a time, and the veggies are nearing harvest. Now that rains and cooler weather are predicted, I’ve put it back on again.
Often at this time of year I’ll set up the cold frame over a bed with starts. It’s amazing to check the soil temperature inside the cold frame and in the bed next to it. Inside the bed, the temperature of the soil will be well above 60, while in the open garden the soil temperature is inching down toward the mid-50s. Capturing that warmer soil temp, keeping it from dropping so fast, is a key benefit to season extension.
Also this week we’ve had a couple of days of significant rain. At times, it’s come down pretty hard. A soft rain is great for watering the beds, and I open the season extension devices for a few hours in early afternoon if a light rain is coming down. The best situation is a nice soft rain for an hour or two, followed by a clearing and light breeze, so the plants dry out. Regular moisture on the leaves and stems of fall veggies can promote rot. If I can’t get the timing right to open the season extension during a light rain, I hand-water the beds as needed.
And I always keep the devices closed during a heavy rain. Over time, heavy rains will compact the soil, leach out the nutrients, and reduce those soil temps — all things I’m trying to avoid. Score another benefit for season extension.
The winds are also gusting this time of year. Combined with cooler temperatures and rain, the wind can be hard on tender vegetable crops. The worst effect is when it blows the top layer of
mulch away from the base of the plant, exposing the plant’s fine root system. Those roots will dry up, making it tough for the plant to survive, much less grow. Such stress will invite pests, and can trigger the plant’s desire to bolt and go to seed.
One final idea concerning season extension: what’s good for the plants is also good for the pests. In this sense: the pests love the warmer, drier location too. I’m picking a lot of slugs and snails out of my season extension devices right now, and off the plants. I need to be diligent about this, because they’re all drawn to the warm place with plentiful food. As the temperatures continue to drop they’ll become less of a problem, but right now, I need to pay attention if I want to keep those fall crops around for my autumn dinners, and not just be feeding the pests.
Fall in the maritime garden is a time to appreciate our weather. The change is usually not abrupt, giving me a chance to also adjust my own pace to the slowing rhythm of nature. But the decline into winter is inevitable, which is another lesson. At this pace, it seems more possible to stay in the moment, enjoying the color and patterns of those fall leaves as they naturally mulch the margins of my garden.
I got out the plant blankets.
Going into last weekend, it became pretty clear that we were headed for a cold front, so I pulled out a few extra pieces of floating row cover and visited my cloches and cold frames. I laid the FRC directly on the plants, doubling it over the salad greens like lettuce, which are my most tender crops.
Sure enough, cold and snow came a-calling.
Two types of cloches protect plants in my front yard.
And the hot caps are still doing their job.
Meanwhile, in the rear garden, all the season extension devices are white. Not a lot of solar gain getting through them, but the snow makes a good insulator against the cold.
Some plants were not bothered at all…
while others took the seasonal change pretty hard.
And as to the fate of many of the plants, only time will tell. I will not be opening the season extension devices and pulling off their extra blankets until the weather warms back up to its seasonal temperatures of mid-40s daytime/high 30s nighttime.
Thanksgiving morning I went out early into the garden for a few final herbs for the turkey stuffing, and a warm rain misted my face. I zipped open the cloche to send the breeze through the salad greens, ready for picking.
Over at the cold frame, which is bursting with more salad, the soil thermometer read 52 degrees. The tiny Cascadia peas in the back, which I intended to overwinter for next spring, are flowering.
And I took the plunge into the chillier (45 degree) wet soil under the floating row cover to grab some carrots, yellow and orange.
I took a tour around the yard to see how the other veggies are faring under my various season extension devices. Found the small Siberian kale (which, in defiance of its name, had been floundering on its own) was looking pretty perky under a row of three “hot caps”: a plastic dome and two dirty yet effective glass bells.
Finally, the dino kale, which did not get the nod as part of the Thanksgiving feast, impressed me as usual with its rich bluish color and bushy sprouting of dark new leaves.
Seeing all the greenery, basking in a warm mid-’50s breeze on a day that was to reach nearly 60, clearly there was a lot to be thankful for.
The rain didn’t dampen my mood as I chopped the herbs into the stuffing mix and readied the turkey for the oven. Note to self: next time, go a little heavier on the herbs: though ours are garden-fresh, they’re just not as pungent as those from our local farmers available at the market.
We sat down to a dinner that included a half-dozen types of produce from our garden, the rest from Northwest farmers, and wines from the region. More thankful feelings all around.
Later we enjoyed a stellar pumpkin pie that Susie made from our own “Cinderella coach,” the heirloom Rouge vif d’Etampes pumpkins that had been decorating our table since Halloween.
As the holiday waned into a big football win by our hometown Seahawks, I saw the warning on Cliff Mass’ weather blog about a cold snap coming. I made a mental note to get out into the yard again on Friday morning to add a little extra protection to the plants.
Cool-season gardening means paying attention to those rumors and reports, and timing it just right to make sure all your effort doesn’t amount to a soggy pile of wilted leaves after a cold snap. Or a bout of snow, which was also in the forecast…
Renewable, natural and compostable. Often available for free. Those are the main reasons why I’ve been making hoop house cloches with bamboo, and now’s the time to get some bamboo and try it, so they will be
ready for covering spring crops.
If you’ve heard my presentation on building a cloche, you know that I don’t think very highly of PVC. The white plastic pipe that is the standard product for building a hoop house cloche in our region is actually kind of a nasty choice. It’s the opposite of all those adjectives I used for bamboo.
I want to focus on how to make a cloche with bamboo, but first, a couple of quick comments about PVC.
Polyvinyl chloride pipe is a traditional plumbing product, quite necessary in some applications, and is readily available for only a couple of bucks a piece. But its cheapness hides its cost to the environment. In the manufacturing process, production of it gives off dioxins, a known carcinogen, which sickens workers and affects the environment. It’s not readily recyclable and would live in a landfill forever. (Learn more than you want to know at Wikipedia’s PVC page, which includes plentiful links to sources and studies.)
I used PVC for years, but as I learned more, I started to move away from it, and looked for other products for my cloche. Fortunately, I found a few options:
Each of these products has their benefits and drawbacks. Wire lasts a long time, but it is not very sturdy, so the hoops are a bit wobbly and have to be placed pretty close together. Wire mesh is more difficult to remove when you want to work in the bed. Fiberglass poles can get brittle and snap if made into a tight hoop, and I haven’t found ones that are very long, so a cloche made with them is shorter. Poly pipe, the black stuff used in garden irrigation systems, gets soft in warm weather and gets floppy (however, it doesn’t have the nasty manufacturing problems of PVC).
I have hoops made of all these products, but the one that I have the most hope for is bamboo.
It’s very flexible when it is young and after it’s just been cut. When it dries, it becomes stiff and holds its shape. Which means… it’s not just for teepee trellises any more!
Here’s how to make bamboo hoops:
1. Find a friend with a stand of bamboo , and cut a half-dozen culms that are 1/2 to 1 inch in diameter and 12 to 15 feet long. Look for pieces that are lighter-colored than the more mature, larger pieces. These will be more flexible. I’ve found bamboo to be more flexible in the spring, and have learned that it can’t be bent into extreme arcs. If you bend it too far or it’s too woody, it will break with a loud crack along the top of the hoop.
2. Strip off all the leaves. A sharp pair of pruners helps with this job. It’s OK to leave the stubs to be smoothed off after the bamboo has dried.
3. Cut off the very flexible top 2-3 feet. This part would bend or break quickly when used.
4. Cut off the stiff bottom end to make a stick about 8 feet long.
5. Stick one end into the ground 6-12 inches, along the inside edge of a raised bed that is 3-4 feet across. This works best with a raised bed made of wood or some other rigid structure, because the bamboo will exert force against it.
6. Grasp the other end with both hands and pull it slowly down into a hoop shape to the opposite edge of the raised bed, then also plunge it into the ground 6-12 inches. Make sure it is securely in place before you let go, because if it’s not, it could spring back out and whack you. Please try to avoid this; trust me, it’s painful.
If you don’t have a raised bed, an alternative method is to bend the bamboo between two other hard surfaces, such as a wall and a set of steps. Pick an out-of-the-way location, because it will have to remain there until it dries.
7. Repeat this process until you have as many hoops as you’ll need to cover your bed, spaced 12 to 18 inches apart. If you need extra help to hold the hoops into their shape, bind them tightly with plastic zip ties, which can be cut away when the bamboo is dry.
8. After a few weeks it will start to dry and you can use it, but it will take 2-3 months for it to completely dry and turn from green to brown. Once it’s dry, it will retain its hoop shape.
9. Trim off the rough edges of the leaf stubs at each node so there are no sharp edges that would rip the plastic. After it’s dry, you can smooth them with a file or sandpaper if necessary.
An 8 foot piece of bamboo placed into a raised bed that’s 4 feet across will yield a hoop that’s about 20 inches high. That’s plenty high for growing salad greens or root crops, or for getting your peppers and tomatoes off to a good start.
The hoops will last 1-2 years if the ends are in contact with the ground, longer if they are above the ground and tied to stakes.
This project will definitely continue to be an experiment, and I’ll update this post with any refinements to my technique. If you have tips, please drop me a note or a photo to share!
Snow hit my garden this morning, so I took a few pictures before the rain melts it all away.