On the farm, where we are growing a large number of plants, we need ways to change the amount of heat, light, and water that our plants receive. Anything we do beyond sticking plants out the in the field and waiting for them to grow will cost us in time and materials, so you can be sure we wouldn’t use methods if we weren’t convinced the techniques paid us back for our efforts. The payoff may come in being the first to market, extending the growing season, providing some insurance against an unusual weather year, reducing weed competition, or even reducing plant disease. We’re not doing anything that couldn’t be done in a backyard garden. We’re just working on a bigger scale and with a smaller budget for each plant.

Low tunnels, drip line, plastic mulch, row cover, raised beds, hoophouses and shade cloth are the seven techniques I’m writing about today for manipulating the growing conditions around our crops.

Low tunnels act a miniature greenhouses, so tulips bloom earlier.

I took this photo a few days ago because it is such a graphic illustration of the effect of the ability of low tunnels to boost the growth of plants by gathering heat.  You can see that the tulips inside the low tunnel are blooming, while the plants outside still have quite a ways to go. Low tunnels are simple. Here Famai has used sections of irrigation pipe purchased at the nearby hardware store to make arches. He has draped plastic sheeting over the arches and buried the edges with soil. One advantage of using the pipe is that Famai can walk through the low tunnel and pick the tulips without disrupting the tunnel itself. In fact, Famai has already harvested half or more of the tulips in this low tunnel.

Low tunnels boost the growth of young plants.

This is the the type of low tunnel I like to use. The hoops are heavy gauge wire and the tunnels are much lower, significantly reducing the cost of the tunnel. I use the tunnels to protect the transplanted plant starts from cold nights and to give the plants a more rapid start. We remove the plastic once the plants start to flower or grow tall enough to touch the plastic. You can see that this plastic is perforated for ventilation. I used this type one year, but I much prefer plastic with slits for ventilation. The slits allow us to reach inside to hand weed around the plants. It turns out that low tunnels are also excellent for boosting the growth of weeds!

Supplying the right amount of water to the growing plants can be a challenge. Right now the soil in our fields is still mostly saturated with water due to the winter rains. However, it is surprising how little rain we receive in the summer. If we want our plants to thrive, we need to deliver water to the plants. Overhead sprinklers are tremendously wasteful of water; when the air is dry, most of the water never reaches the soil. In any case, hauling sprinklers and hoses over acres of fields takes up huge amounts of time that could be spent on other tasks.  We use drip irrigation wherever possible. Installing the drip system each spring takes up valuable time when we are already very busy, but once set up, we just need to open and close valves to control the water flow. Plus, the water is delivered directly to the soil, greatly reducing losses due to evaporation.

You can also see the black pipeline in the photo above. This pipe carries irrigation water along the edge of the field. At each row of plants you can see a tube branching off to deliver water to that row. The thin tubing has outlets at regular spaces. I like the 6-inch spacing. The tubing collapses flat when there is no water pressure, so it is commonly called drip tape.

Row cover fabric protects tiny plants. Onion starts do fine without.

I took this photo and the next when we were still growing vegetables for sale at the farmstand. The row covered with the thin white fabric has been planted in bok choy and other Asian vegetables. Row cover can serve some of the same functions as low tunnels, but without the hoops to raise the fabric off the plants. The row cover is thin and light enough to let the rain pass through. The fabric is laid loosely over the row, so the plants can grow, pushing up the fabric. Another major benefit of the row cover is that it blocks incoming flea beetles and other pests from reaching the plants. If you have seen tiny pinholes in Chinese cabbage, bok choy, arugula, or other greens then you are most likely seeing flea beetle damage.

The three beds to the right have all been planted with onions. All these were planted in holes punched through a very thin black plastic.  The black plastic gathers the heat from the sun, warming the soil below, and giving the plants a heat boost. Another major benefit is that the plastic blocks the weeds from growing, so we only have to weed where we have punched through the plastic. Last year the plastic mulch really paid off. In a difficult year for winter squash, our farm had much greater success than our neighbor farms.

Another advantage of the plastic is that it keeps the soil moisture from evaporating. Since the drip tape is under the plastic, all the water stays in the soil, available for the plants. Drip tape under plastic is even more efficient at conserving water than drip tape lying on the ground.

The plastic mulch is laid using a tractor-mounted implement that rolls out the plastic and covers the edges with soil to hold it in place. We have also laid plastic mulch by hand. The tractor is much faster, and does a better job, too.

A thin sheet of plastic warms the soil, giving the plants a boost.

This photo illustrates a number of techniques. The very front row is a red lettuce not long transplanted out. The next row looks like romaine lettuce. Behind that is a row of rainbow Swiss chard. The next row is spinach, followed by two rows of red or green lettuces, some ready to harvest.

Here you can see that the plastic is stretched over raised beds. We have a tractor-mounted implement that scoops up the soil to raise the level of the bed, while at the same time stretching the plastic mulch over the bed.

I like to use raised beds early in the season when we still might get a fair amount of rain. Raising the top of the bed those few inches lifts the plants up out of the puddles, so the roots are less likely to smother from lack of air. Also, it is amazing how much raising the top of the bed those few inches helps your back muscles when bending down to tend the plants.

In the background you can see several of our hoophouses. Hoophouses, also call low tunnels, are simple structures of plastic sheeting stretched over a framework of pipe. Typically we use the term hoophouses for structures that are not heated and where we grow plants directly in the ground inside. Usually we use hoophouses to extend the season, either to be early to market or past the early frosts. I’ve used one to grow bigger pumpkins than I can grow outside.

Here in the Pacific Northwest growing tomatoes in a hoophouse is an excellent way to prolong tomato production. In the fall when the rains start, the tomato plants outside typically get late blight and die in a few days. The organism causing late blight is splashed up onto the plant with the soil. Sheltering tomato plants from the rain and watering them with dripline lying on the ground may mean several additional weeks of tomatoes in years when the rains come early and the frosts come late.

We may add roll up sides to spill out excess heat on hot days. We may add a thermostat-controlled exhaust fan if we don’t want count on always opening the doors or rolling up the sides on time. We may add fans inside to move the air around to reduce the chance of moisture-induced fungal infections. We may add a second layer of plastic on the roof with a small fan blower to puff up the top layer and add some insulation. We may add a heater, but by that time we are calling the structure a greenhouse, rather than a hoophouse.

We use this hoophouse to grow plant starts for transplanting.

We also use hoophouses to start seedlings for transplanting out into the field. We can start the plants in the hoophouse before we would risk planting the seeds directly into the soil, and them transplant them out when it is a little warmer. If the summer is cooler than average, that extra growing time in the hoophouse may make all the difference in a successful harvest. Putting growing plants in freshly prepared ground also gives our plants an important head start over the weed seeds, which are sure to sprout in abundance. Except for the corn in the corn maze, we transplant most of the plants on our farm.

We have made a number of changes to this hoophouse to make it more useful as a starts house. We have put weedblock fabric down on the floor. This is not strictly necessary, but it does keep things tidier as well as keeping our feet out of the mud that would result from daily watering. We have put in tables to raise the plants to a better working height for us. We have added a greenhouse bench in the far corner where we fill the seeding flats with the seedling mix and poke a seed or two into each space. You can’t see them in this photo, but we have added roll up sides and a thermostat-controlled exhaust fan at one end. A hoophouse can heat up remarkably quickly on a sunny day. One afternoon of unexpected sun could kill off most of the tiny plants in the house in a few hours. That could mean that we could not grow those crops that year, resulting in a tremendous financial loss. Crop loss due to weather such as hail or windstorms is difficult to deal with. Loss due to forgetting to open the hoophouse doors would be much more painful.

When summer is in full swing, we have one more tool to moderate the hoophouse temperature. We add shade cloth over the house to reduce the temperature buildup.

Shadecloth is a woven material used to cut down light intensity.

Shade cloth is a loosely woven black fabric. It comes in various percentages in light blocking. I enjoy looking up through the fabric from below when the birds walk about on the fabric.

We use shade cloth to moderate hoophouse temperatures, but shade cloth is most commonly used to provide shade. Nursery growers routinely use shade cloth when growing shade-loving landscaping plants. When grown in an open field, some commercial crops, such as ginseng, are only successfully grown under shade cloth. Farmers in hotter regions have been successfully experimenting with using shade cloth to help them extend the growing season for cool-season crops such as lettuce and other greens further into the heat of the summer.

So, no big secrets here. No high tech. Nothing that couldn’t be used by any grower from a tiny backyard garden all the way to a huge farming operation. The only difficult calculation is whether using one of these techniques will pay back the time and effort to use it. And like so much else in farming, it all depends on this year’s weather.

]]> http://drmazesfarm.com/farmerroger/2010/03/13/7-techniques-microclimate-manipulation-tools-techniques-farm-part-2/feed/ 0 http://drmazesfarm.com/farmerroger/2009/04/02/searching-for-a-silver-lining-during-rain-calamity-week/ http://drmazesfarm.com/farmerroger/2009/04/02/searching-for-a-silver-lining-during-rain-calamity-week/#comments Thu, 02 Apr 2009 23:03:34 +0000 Farmer Roger http://south47farm.com/farmerroger/?p=20 There’s an old saying: “Inside every cloud there is a silver lining.” I am in the habit of searching out the silver lining, something to keep me focused on the positive, since there are so many ways things can go wrong on the farm.

This week it looked as if the clouds had dumped all their water on the farm, so it seemed to me the remaining clouds must be comprised mainly of silver lining. After much looking around the farm, I did find the silver lining looking back at me. You’ll have to read through a lot of calamity to get to it though.

In the 40 days since February 22 only eight days produced no rain as measured by our farm weather station. The soil is saturated with water, so additional rain collects on the soil surface in large sheet puddles as it works its way across the farm toward the Sammamish River.

Typically the rainy periods are separated by dry days, when the soil dries out enough for us to prepare the soil for planting. This year the soil just hasn’t had a chance to drain.

We have managed to get crops planted out on time so far. We prepared an area for the leeks, which are coming along nicely. We have lettuce, spinach, and other crops planted in two hoophouses, where they are now taking hold. We were able to put in two beds outside for collards, mustards, & other hearty greens. We planted kohlrabi in extra space by the leeks. Our first planting of peas is in the ground. We got a lot of compost spread while we could still drive on the fields.

Now we have hit a hard place. The greenhouse is filling up with lots of tiny plants that should be planted out soon, but the soil is too wet to work with. This week’s series of storms may put us too far behind planting schedule to catch up. We could be forced to dump thousands of tiny plants into the compost pile.

On Monday, it rained a little. I knew a storm was forecast for Tuesday, but I was willing to be optimistic that we would get past the storm and back on schedule. That same day I was hit with the worst head cold I’ve had in years, but that would also pass.

The rain hit Tuesday morning. The winds picked up quite a bit. We lost power for a couple of hours. My nasty cold was still turning my brain to mush. The wind tore the plastic cover off of one of our hoophouses. We have been using that house to shelter equipment and other supplies, so the crew spent some time covering things with tarps and repairing minor damage on our other hoophouses in the hope of keeping the wind from causing more major damage. The rain on Tuesday totaled 0.2 inches. I knew another storm front was forecast for Wednesday, but I was still thinking that if the coming storm wasn’t any worse we had a good chance to get back on track with just the storm damage to repair.

On Wednesday morning (April 1) the rain started at about 8:30 and continued heavy all day. The farm received 0.6 inches for the day. That may not seem like a lot at first glance, but the whole farm was already in puddles. Now the puddles could just get bigger and bigger. We mostly found work under cover. Juan & Luis built greenhouse tables for our retail vegetable plant sales. Rob did maintenance and went out to purchase plastic to repair the torn hoophouse cover. Evert & Stewart planted tomato and other seed in flats in the greenhouse. Although out of the rain, they needed their rubber boots, since a couple inches of cold water was standing in much of the greenhouse. Claire & I agreed it was time to start making desperation plans in the event that we fell impossibly far behind on the planting schedule. Looking at the forecast for more rain coming the next day, it was hard to dredge up any optimism.

Today, Thursday, I woke up to find my sinuses cleared. Maybe today would be a turning point. However, looking outside, I realized the rain was coming down hard. In fact, today we received even more rain than yesterday – 0.65 inches by 4:00, when I’m writing this. Evert and Stewart worked in the starts greenhouse again today, but now they stood in a stream of ankle deep water running through the greenhouse. Juan & Luis worked in the rain putting the new plastic cover on the damaged hoophouse. Rob, with help from Juan & Luis, spent most of the day on the tractor working to channel rain runoff and improve drainage.

All day I watched puddles getting larger, water rushing across fields, and plants slowly submerging. Late afternoon I talked a while with Famai, one our renters, who was also unhappy and frustrated with the drowning fields. As I walked past the beds where Evert had planted peas, I thought I should take a look. The peas were just about due to sprout. There is nothing like new sprouts poking their way out of the soil to cheer things up.

Instead of new green sprouts, I found peas with nice two-inch roots lying on the surface, where the rain had washed them out of the ground. I knew these would not survive, and worse, would attract the crows to the sprouting peas. Once the rain stopped and the crows came out looking for lunch, we could lose most of the planting.

I stopped off at the starts greenhouse to talk with Evert about how best to rescue the peas. I mentioned to Evert and Stewart that I had gone to look at the peas hoping to find a silver lining to counter all the problems of the week.

As I was saying that, I looked at the two of them smiling back at me and it struck me that all day long, in difficult and frustrating working conditions, each and every person on the field crew, Rob, Juan, Luis, Evert, and Stewart, had a smile for me when I stopped by to see how things were going. Everyone was making the best of a trying day.

I had found my silver lining, smiling right back at me.

First daffodil of spring

I’m still enjoying the display every time I walk past. The massed yellow flowers are a constant reminder that the weather will eventually change.

Spinach Seedlings

We have a lot of work to get ready for the farm opening on May 13. The greenhouse is filling up with tiny plants.

Lettuce, spinach, frisee, bok choi, & salad turnips were transplanted into the hoophouses already by mid March. The first outdoor planting was leeks, planted on the first day of spring. Four of the crew started back at work four weeks ago. By the end of the day today, we’ll have spinach and kale planted outside, and the first peas will be planted soon.

Evert planting spinach

Rob

Evert has done all our greenhouse starts the last two years. This year he will be in charge of vegetable production from start to harvest, with Claire providing planning and expertise. Evert will have a small group who will focus entirely on vegetables, herbs, and flowers. Today Evert is focused on transplanting out the spinach & kale and setting up to start about 1300 tomato plants for Chef Brian. Rob is back in charge of the general field crew and all our equipment. Rob has been dealing with the spring equipment breakdowns, as well as a large number of projects around the farm and directing the field work. Today Rob is working on grading the potholes out of the gravel road.

Juan planting spinach

Luis with shovel

Juan (left) and Luis (right) are both back. They will be doing the general field work, pumpkins, winter squash, gourds, and the corn maze, and any special projects. This month they have also been helping Evert with the vegetables. Today, for example, they set up raised beds where Evert will plant peas in a few days, laid out two planting beds outside for spinach and kale and are heading down to finish changing the clear plastic over the big starts greenhouse. After lunch they will help Evert plant the spinach & kale.

Stewart on his first day at work

We hired Stewart to help Evert with the vegetables. I took this photo two days ago on his first day at work. Stewart is a chef starting over as a farmer, following his food passion to the source.

Chris is putting the final touches on the announcements of our brand new Free Choice CSA. We’re pretty excited to be finally offering a CSA at The South 47 Farm. We think giving our CSA members free choice will appeal to people who want to join a CSA and support a local farm but don’t want to be tied into a “box of the week” style CSA. We will still be working to surprise and delight you, but you get to choose which surprises you take home to supper.

There’s a lot more I haven’t talked about here. I do several microblogs a day on Twitter. Check them out at http://twitter.com/FarmerRoger.