landscape fabric – Sustainable Market Farming

Hoophouses I visited this month

In early November, during the Carolina Farm Stewardship conference I went on the afternoon bus tour to see 10 high tunnels and how they’re used for season extension, irrigation, disease control, pest protection, and trellising. Red Hawk Farm grows salads and greens year-round in six high tunnels (more under construction!), and sells primarily to local grocery stores and restaurants. Funny Girl Farm grows produce year-round for its popular farmstand and CSA, with four high tunnels and a greenhouse.They were focusing on the sweet potato harvest outdoors when we visited.

Red Hawk Farm hoophouse densely planted with multileaf lettuces.
Photo Pam Dawling

At Red Hawk Farm I was astounded to see this whole hoophouse planted wall-to-wall with multileaf lettuces. No aisles! The farmer Brett Evans plans to harvest with a walk-behind motorized salad harvester machine that makes a 4 ft wide cut. Then he’ll leave the lettuces to regrow. He uses the paperpot transplanter which I mentioned last week. Here are the starts growing in their propagation house.

Lettuce starts in paperpots at Red Hawk Farm.
Photo Pam Dawling

They still had peppers bearing well in one high tunnel

Early November pepper harvest at Red Hawk Farm.
Photo Pam Dawling

Another interesting feature was the opening roof vent, which I had not seen in operation on a hoophouse before.

Opening roof vent on a hoophouse at Red Hawk Farm.
Photo Pam Dawling

And this past week, I went to Potomac Vegetable Farms in northern Virginia for a talk with Future Harvest CASA members, and a tour of the hoophouses used there led by farmer Zach Lester. I was interested in seeing the success he is having with caterpillar tunnels. These are smaller tunnels with a single layer of plastic, held in place by ropes, as you see in the photo below. They can be temporary or short-term, and Zach showed us one which is a “swing house” with two sites side by side, sharing one row of ground posts, and having just one row to move each time. Another way to deal with crop rotations and reduce the chances of pests and diseases!

Caterpillar tunnel at Potomac Vegetable Farms.
Photo Pam Dawling

At the ends, the plastic is gathered up and tied to well-anchored stakes, as you can see here.

How the ends of caterpillar tunnels are gathered and fastened to stakes.
Photo Pam Dawling

Zach got these frames custom made by Nolts. They have taller sidewalls than many models. He is also a firm believer in having a ridgepole in caterpillar tunnels, to reduce the likelihood of collapse with snow or high winds. As you can see here, they had some snow already.

Potomac Vegetable Farms caterpillar tunnel showing rolled up side.
Photo Pam Dawling

At both these farms, I learned the technique of laying landscape fabric along the side walls to reduce weed growth. You can burn holes in the landscape fabric where the ground posts go through, and it will keep the weeds away for a long time. I wish I’d known that technique when we put up our hoophouse. We have to hand weed, and in some places we have wiregrass (Bermuda grass) which has grown under the baseboards and even between the boards where there are joins.

Lastly, I have of course visited our own hoophouse at Twin Oaks, and have written a post for Mother Earth News Organic Gardening on Dealing with Snow on Your Hoophouse. So if it’s snowing where you are, you can click on the link to read about that.

Adapting to a wet spring, using cold frames

Our greenhouse full of seedlings in spring. Photo by Ira Wallace — Our greenhouse full of seedlings in spring.
Photo by Ira Wallace

Our greenhouse is full of flats of seedlings. Today is warm and sunny. At last! The soil is still too wet to till, but we are feeling more optimistic. The forecast still has possibilities of rain Tuesday night (only about 0.1″) and snow Friday night (less than an inch). Soon we will start moving flats from the greenhouse to our cold frames so the plants can harden off in preparation for transplanting in the raised beds. Usually we would have done this earlier, but it has been cold.

Our greenhouse construction is a masonry north wall and double-paned glass windows and insulated walls. Until last winter we didn’t use any additional heating, just the sun. But we now use an electric heater with the thermostat set so heat comes on if the temperature drops below 45F. We decided our seedlings are too precious to risk freezing them, and the weather is more extreme. We also put row cover over the seedling flats if the night temperature could fall below 18F outdoors. Once we have frost tender plants outside the plastic tent (which has a heat mat), we put row cover over those if the outdoor low temperature could be below 28F.

Our cold frames are built from loose set cinder blocks, higher on the north than the south. Following advice from Eliot Coleman in one of his older books, I think Four Season Harvest, we slope the soil in our cold frames. It’s higher at the north, by about 7 degrees, so the plants get better sun exposure.

In late summer, we dig compost into the soil in the frames, rake it up to the angle we want, and sow the spinach in mid-September.

Digging compost into our cold frames in early September. Photo by Wren Vile — Digging compost into our cold frames in early September.
Photo by Wren Vile

The spinach grows in the ground in the cold frame all winter.When it gets cold enough, we cover with row cover. During cold spells we add lids which are wood frames with fiberglass glazing. For very cold nights we cover the cold frames with quilts which are made from reject scraps of the quilted hammocks Twin Oaks sells. Because they are made for outdoor use, the fabrics are very durable.

Here’s how we look after our cold frames in spring:

If there is only spinach in the frames (no flats), use rowcover for temps >10F, rowcover and lids for <10F. No need to open and close every day, just remove or add lids if the weather is changing. See below about windy nights.
When there are flats in the frames, at night, use the rowcover for temperatures 32-40F, rowcover+lids for 15-40F, rowcover+lids+quilts for temps below 15F. If winds are forecast to be more than 20mph, weight down the lids with wood. If you’re using the quilts, weight them down for winds more than 5mph.
In the morning, if the temperature is over 20F, roll up the frame quilts if used.
If the air temperature is over 50F, or over 45F and rapidly warming, open the cold frame lids if used, and remove any rowcover over flats, until it cools down again. Seedlings need to harden off, to prepare them to survive outdoors.
Keep cabbage and broccoli over 40F, tomatoes, eggplant, celeriac over 45F, peppers over 50F.
Flats of seedlings which have been up for a couple of weeks usually need to go to the cold frames for the last two weeks before their transplant date. Good to check about this though, and don’t do it if the weather is about to turn colder. Don’t put celery, eggplant, cucumbers, squash or hoophouse starts in the coldframe at all.
If the soil surface is dry, run the drip irrigation for the spinach, or use the hose and sprayer for the flats. If frost is possible, disconnect the hose from the faucet and the sprayer head from the hose when finished, so that they do not freeze and burst at night. Please store the sprayer head in the blocks, don’t get sawdust or dirt in it, it’s a pain to clean. If the outdoor faucet is drained, carry water in cans from the greenhouse. Keep soil surfaces damp, not wet.

Our greenhouse and cold frames in spring with flats of seedlings. Photo by Kathryn Simmons — Our greenhouse and cold frames in spring with flats of seedlings.
Photo by Kathryn Simmons

For a few years we have had trouble with voles eating the roots of the spinach. We found that if we replaced the spinach with flats of seedlings, they ate all the seedlings! So now, we leave the frames empty for a few days after clearing the spinach (any day now). Then we cover the soil with landscape fabric and put the flats on that. it saves our seedlings.

Strawberry propagation, Heritage Harvest Festival

The September issue of Growing for Market is out. For this issue I wrote about our efforts to find a sustainable method of growing strawberries. We now use landscape fabric with holes melted in it, and keep the plants for two years. We are rebuilding after some years when the weeds overcame our previous beds, which had organic mulch (newspaper and hay). Our plan is to have two patches, and till in the two-year old one after harvest (after removing the landscape fabric and drip tape of course!), and make one new patch each summer. We’re a bit late this summer, but the system has promise, and I am optimistic!

Our new strawberry bed, using landscape fabric. Credit Wren Vile — Our new strawberry bed, using landscape fabric.
Credit Wren Vile

In the past we have tried buying dormant plants in the spring (disadvantage: needing to weed the plants the first year and getting no fruit until the following year); buying plugs in fall (disadvantage: expensive) and various methods of propagating our own plants (mixed results).

We have tried keeping the plants for four years (disadvantage: way too much weeding); keeping the plants for two years (better); and accidentally keeping the plants for one year only (disadvantage: expensive).

We have tried organic mulch (disadvantage: lots of weeding); black plastic (disadvantage: unsustainable use of fossil fuels, and disposal was a pain); and now – landscape fabric. You can read all about how we do that in GfM.

As for the various methods of propagation, our current favorite is to grow our own plug plants from runner tips, using a home-built mister/fogger system. Our traditional method of propagating was to prepare new beds in late summer, then dig up runners from the paths or beds of the established plants and move them directly to the new beds. Success with these “Fresh Dug” plants relies on two weeks of intensive watering after planting. We also tried a method that worked well for me in England – pegging runners (still attached to the mother plants) down into small pots of soil for a few weeks until they had rooted, then snipping them from their mother plants and setting out a new bed. This works in rainy climates, or with overhead irrigation, but it didn’t work for us once we switched to drip irrigation. What a lot of trial and error!

New strawberry plants popped into the holes in the landscape fabric. Credit Wren Vile — New strawberry plants popped into the holes in the landscape fabric.
Credit Wren Vile

In my article, I mentioned cutting “runner tips.” These are small unrooted runners, that need potting up and keeping alive for 4-6 weeks to grow into plugs. Here are instructions for the 6-8 week method we use when we propagate our own plants:

July 1-7: Fill 50-cell plug flats with screened compost. Water to activate the soil
July 8-14: Harvest runner tips or young runners, using pruners. Clip with ½” of the runner attached, to act as an anchor for the young plant. Choose runner tips with
- 2 or 3 open leaves 2½-4” long (not more, not fewer, the researchers say).
- “Pegs” or nubs of developing roots, or roots up to ½” in length.
- Large diameter crowns – pencil thickness if possible. Large = more flowers next year.
- First or second position on the runner, not more distant from the mother.
- Clip off any secondary runners coming from the daughter plants.
- Sort the tips by size, planting that same day in 50 cell plug flats with like-sized tips, for best results.
- Put the flats in a coldframe, water well, cover with thin white poly sheet (bin liner type), lightly perforated. Add shadecloth. Keep moist by watering daily as needed.
July 15-21: Continue daily watering. Remove shadecloth. Count live plants, harvest and pot more as needed.
July 22-28: Continue daily watering. Remove plastic, replace with rowcover. Harvest and pot more as needed.
July 29-Aug 4: Continue daily watering. Remove rowcover. Harvest and pot more if needed.
Aug 5-11: Continue daily watering. Harvest and pot more if needed. Remove shadecloth, plastic, rowcover from later harvested plants when appropriate.
Aug 12-Sept 1: Plant two staggered rows with plants 12” apart in all directions. Choose the biggest healthiest plants – it makes a lot of difference to the yield!

I reckon in our climate mid-September is about the last date for planting out new strawberries. If we miss that date, we should probably wait till February and lose a year’s production. Sad thought.

I want to explain how the 1/2″ of runner acts as a peg to hole the runner tip in the soil. No-one explained this to me when I first tried it, and at first it made no sense. Push the anchor at about a 45 degree angle into the soil in the plug flat. When the anchor is all in the soil, press down with your thumb on the side of the crown of the plant opposite the anchor and turn the plant to stand it up. When you get it right it’s a wonderful thing – quick and elegant.

And I should say that propagating from unpatented varieties is fine, but propagating from patented varieties, even for your own use, is annoying illegal.

Meanwhile, I’m preparing my presentations for the Heritage Harvest Festival. If you are anywhere in central Virginia, consider going to this lovely event at Monticello, near Charlottesville. The weather forecast is very pleasant, the setting is delightful. Saturday 9/7 is the day. Click the link to read about the schedules, the vendors and the fun events. On Friday at 9am I’m doing a presentation on Asian Greens (there’s still some $10 tickets available for that one) and on Saturday at 10.30 I’m doing Succession Planting. That one is sold out. I’ll also be doing book signings at the Monticello Store after each of my workshops.

After the weekend, I’ll post my slideshows on SlideShare.net, and probably embed one in my next blog post, for those who miss the live show, and those that want to watch it again.

Goodbye winter, hello summer!

Rhubarb season is almost here. Credit Kathryn Simmons — Rhubarb season is almost here.
Credit Kathryn Simmons

Spring in Virginia is so variable in temperature! But this year is more so than usual. We’ve just had three days with high temperatures of 90F (31C) or more. Not so long ago we had night-time lows of 20F (-6.5C). Late February and all of March was full of snow and rain.

The only thing we managed to plant in the garden for the whole of March was a small amount of shallot bulbs. We’ve been doing an impressive amount of scrambling in the first ten days of April, to make up for lost time. Some crops we had to cut back on, because it got too late to plant. We only have a quarter of the onions we planned, half of the peas, a fifth of the spinach, and no fava beans this year. I realize it would be useful to have “last worthwhile planting dates” for all our spring crops, to help decision-making.

To add insult to injury, a Beast ate half of our early broccoli transplants in the cold-frame one night. Because there were big surface tunnels, I think it was Eastern Moles. They are insectivorous, not vegetarian, but they do use leaves to line their nests, which they make at this time of year. I bought a trap – no luck. I covered the remaining broccoli and lettuce flats as best I could with rat wire “lids” and clear plastic domed food covers – things I had handy from previous depredations. What seems to have worked is to line the coldframes with landscape fabric and set the flats on that, tightly up against the edges, leaving no wiggle room. Wisely, we do a later, third, sowing of broccoli to cover emergencies, so we spotted those out into bigger flats. We’re going to need them this year.

Chitting seed potatoes ready for planting. Credit Kati Folger — Chitting seed potatoes ready for planting.
Credit Kati Falger

Newly emerging potato plant in the spring Credit Kathryn Simmons — Newly emerging potato plant in the spring
Credit Kathryn Simmons

We have at last got our potatoes in the ground, three weeks later than ideal. On the positive side, they had been chitting (green-sprouting) in crates under lights in the basement since the beginning of March, so I could console myself that they were growing anyway. And probably they will come up quicker in the (suddenly!) warmer soil. We cut them for planting once the area was disked for planting and we were pretty sure we could get them in the ground in a few days.

We’ve busily transplanted spinach, kale, lettuce and scallions, and sowed carrots, more scallions and the third bed of beets. We used the Earthway seeder for the beets, and found the radish plate worked better than the beet plate for Cylindra seed, which were smaller than the Detroit Dark Red. We also tried the popcorn plate with some success, when the beet plate jammed.

We flamed one of our first two beds of beets, to kill the weeds that didn’t die properly with our hasty delayed rototilling. We would have flamed both, but the Cylindra popped up overnight earlier than I expected (going by soil temperature), so we’ll have to hoe those really soon, maybe this afternoon.

Spring bed of cabbages planted into rolled hay mulch. Credit Kathryn Simmons — Spring bed of cabbages planted into rolled hay mulch.
Credit Kathryn Simmons

Next we’ll be prepping our cabbage and broccoli beds. We make temporary raised beds, roll out round hay bales over them, then transplant into the mulch. We do this by first measuring and making “nests”, using our hands to open up the mulch down to the soil. The brassicas appreciate the mulch to moderate the soil temperature and keep some moisture in the soil.

Our big weeding projects have been the raspberries and the garlic.(Goodbye, henbit!)

Today we might sow our parsnips. I just wrote an article about them in the March issue of Growing for Market. This issue also contains articles about increasing hoophouse tomato production, adding solar panels, equipment for tracking the weather, food safety and new interesting cut flowers.

Florence bulb fennel. Credit Southern Exposure Seed Exchange — Florence bulb fennel.
Credit Southern Exposure Seed Exchange

The April issue is also out. For that, I wrote about fennel – bulbs, leaves, seeds and pollen. Other articles include one about Johnny’s Salanova lettuce, others about training cucumbers and tomatoes up strings in the hoophouse, a tractor implement for rolling out round hay bales (which is only fun to do by hand the first ten times, max), more on food safety, and an interview/field trip to Texas Specialty Cut Flowers.

Lots of Rain! Thinking About Strawberries . . .

We’ve managed to work in the garden most of the time we’d planned to this week, even though we’ve had a lot of rain. Since the start of September, in just 5 days, we’ve had 2.4″ and it looks like rain brewing now. Before that we had a week without rain, but before that a week with 2.1″. The soil is saturated, and hoeing anything would be a complete waste of time even if it was possible. We just have to watch the weeds grow in most places, while we focus on what we can do.

Great news on our big carrot weeding – we finished that this morning! I made a new Task List for the week and it mentions a lot of weeding, which sounds daunting. I remind myself that compared to the carrot weeding, most of the upcoming weeding tasks are small. One 90′ bed of squash plants doesn’t take long at all, and even a 90′ bed of turnips isn’t so much!

Zucchini, Grey (Tender Grey) SQUASH, SUMMER 3 g — Tender Grey Zucchini from Southern Exposure Seed Exchange

I saw that our fifth sowing of squash has tiny squashes on it, so we’ll add that to our harvest list, along with the number 5 and number 4 plantings. That’s good news, because I want to “do in” the old #3 planting soon. It’s beside the watermelon, which is just about finished, and I’d like to pull the drip-tape out of there, and roll and store it for next year. Then as soon as the soil is dry enough to not get too compressed by the weight of the tractor, we can disk up that area and sow winter cover crops. Winter rye, Austrian winter peas, and crimson clover in this case, for next year’s mid-season sweet corn.

I just ordered two rolls of DeWitt Sunbelt landscaping fabric (weed barrier) for our new strawberry beds. We’re going to try burning holes in the fabric to plant through. The goal is to have more strawberries and fewer weeds. I’ve met and read about other growers who do this, and it seems to me to be our best hope. We can roll up the fabric and reuse it in a year or two, when those strawberry plants are worn out. Other members of the crew are less enthusiastic than me to try this, so we’ll see how it goes. If it doesn’t work well, I’ll be selling the landscape fabric in June 2014, so watch out for it! Really, though, I do expect it to work well and convince the others.

Strawberries on the plant — Planning ahead for strawberries

Here’s a link to Mark Cain of Dripping Springs garden in Huntsville, AR about Landscape Fabric in the Marker Garden. Erin Benzakein wrote a great article in Growing for Market in October 2011: Eliminate weeding with landscape fabrics. You’ll need to subscribe to read it. These two convinced me. There are a couple of photos on the Black Village Market Garden blog and a whole series on Mountain Harvest Organics, which is over twice our scale.

I’m on the point of ordering strawberry plants too. We’re getting plugs of Chandler strawberries from Cottles in North Carolina. (Call or email them for info on plants, mostly their website is about selling fruit and vegetables.) We bought from them in 2010 and the plants did very well. Plugs are the easiest way to grow new strawberries. They are little plants in plastic cell-flats. Shipping is rather expensive, naturally, because you are getting the potting soil too. But in this area, plugs planted now will be harvestable next year. In the past we used to buy bare root plants, which are just how they sound, and are only sold during the dormant season, for planting in early spring. Then you are not supposed to let them flower the first season, so you have to weed for a whole extra year before getting any fruit.