Category Archives: watering

Watering in the Heat, and more… by Peter Heffelfinger

By Peter Heffelfinger

posted August 16, 2022

Watering in the Heat

The first half of August usually brings the hottest weather of summer, but the impact of climate change has brought more intense heat waves, with the daytime temperatures on Fidalgo Island consistently in the 80’s. We are fortunate, being close to the cooling effect of Puget Sound, which creates late afternoon onshore breezes that can take the edge off the heat. The nighttime temperatures, however, have been staying in the 50’s, even during the heat domes. The cool nights, a harbinger of the fall weather that will start to creep in later in the month, have also created the grey mold on the leaves of the big leaf maples as well as on the foliage of some winter squash.The vegetable gardens, however, still require a great deal of water to deal with the overall summer drought.

Watering the hoophouse paths

The basic garden watering mantras hold: water early in the day, to avoid loss of water to evaporation, and to give the plants time to absorb prior water prior to the daytime rise in temperature; use a protective mulch of some kind to protect the surface of the soil from drying out and to keep the soil moist around the root zone of the plants; and, water deeply on a regular basis, when the soil begins to feel dry to the touch at a depth of 2-3 inches, usually every 2-3 days. Watering too lightly and too often keeps the roots close to the surface of the soil, and the plants are easily dried out on hot days. For some crops that are producing heavily right now, such as pole and bush beans, I water more frequently in order to ensure a sustained crop of tender and sweet beans. Unless you’re raising dry beans or saving seed, remove any pods that get too large and tough in order to keep the plant producing more flowers.

Asparagus and Artichoke plants needing water in August

Fall and Winter Plantings

Mulching the leek beds

It can be difficult to think about fall and winter crops while it’s still high summer, but now is the final window to put in over-wintering leeks, cabbages, late cauliflower, purple sprouting broccoli, and hardy leafy greens. I water the young transplants each morning to give their still-fragile root systems moisture to deal with the intense sun and extended day length of our northern latitude. The reward in late fall and through the winter is a sustained crop of fresh produce that can be harvested from the garden even on the coldest and wettest days.

winter brassica transplants, with grid to support temporary shade cover

Other semi-hardy winter vegetables to consider, which may need some protection from a row cover tunnel, include daikon and black Spanish radishes, non-bulbing leaf turnips, hardy mustard, broccoli Raab, and cold-resistant greens such as mache, arugula, and winter spinach. There is no need to shut down the garden in late fall. The key is to plant early enough in late summer to allow the plants to reach an adequate level of maturity before the cold and short days arrive. The plants then essentially coast through the winter, sprouting fresh shoots, leaves, and buds in response to the warmer days in between the storms. Winter is the fourth season of year-round gardening.

Other Watering

During August one should not forget to water existing perennial beds, such as asparagus and artichokes, which have already produced a main crop, but still need doses of water to keep their root structures growing until the cool fall rains arrive. For standard crops such as corn and squash, regular deep watering is needed to keep them on schedule. I do have some late planted large sweet onions that are still green since they are in half shade, which are still getting a bit more water. The main crop of storage onions, however, has reached maturity, and the half-brown tops have been bent flat to the ground to stop further growth and dry them out in the sun. It’s important as well to know when to turn the spigot off.

Onions drying in the sun

The Hoop House

The hoop house requires a more intense and sustained regimen to keep the tomatoes, peppers, cukes and tomatillos properly hydrated. To prepare for the hottest days I covered half the roof with two 40-foot bands of light green shade cloth, made from recycled soda bottles, as a way of cutting down on the sunlight. Not a drastic reduction, perhaps 10%, but a noticeable effect on the high temps up at the ridge pole, which can easily soar to 95F and above if left unchecked. The temperature down at ground level is usually 5-8 degrees cooler. Tomato plants will drop their flowers in response to the stress of extreme heat of temps above 90F. Being perennial vines, tomatoes will generate new blossoms fairly quickly but the final crop will naturally be reduced. Pepper plants, as bushes, may drop a few flowers even in normal growing conditions, and are slower to re-flower if impacted by high heat.

Given the still-cool nights, I lower the side walls and end flaps of the hoop house in the evening to keep the temperatures inside above 50 degrees to maintain fruit-setting. I open the house early in the day since the first rays of the sun can easily jack the thermometer to 80-90F. The key to cooling the semi-enclosed space is to keep the air flowing. When the weather is consistently hot I water the beds heavily every 2 days, making sure the mulch and the soil around each plant is properly saturated. On the extreme heat days, especially when there is no wind, I take the added precaution of flooding the paths, creating shallow pools between the raised beds to increase evaporation and to make sure the deep roots get water. Two 50-gallon drums on raised platforms with gravity-fed hoses supply the irrigation system for the hoop house. So far, I’ve managed to prevent any blossom drop due to water stress, relying on a well that feeds off the water table coming from the back side of Whistle Lake. This year there has been plenty of water, but in past Augusts the flow of the well has diminished. Hopefully the increased precipitation during recent winters due to climate change will be enough to continue to supply our gardens during the now extended Mediterranean dry summers.

Drip Irrigation

by Julia Frisbie

posted June 3, 2021

Every year when my family asks me what I’d like for Mother’s Day, my answer is the same: to finish setting up this year’s drip irrigation system. By mid-May I begin to think ahead to summer drought, and I also get tired of hand watering all the transplants. Finishing the drip irrigation is a big task, but a fun one (we call it the adult equivalent of LEGOs) and it brings me great satisfaction.

By using drip irrigation, we:

Waste less water by delivering it only where needed
Cut down on weed pressure by reducing the surface area that gets wet
Avoid fungal infections by keeping leaves dry
Put it on “autopilot” when we travel, get sick, or get busy

If you’re worried you might forget or be unable to water, an automatic timer that can be programmed to run every morning is a good investment. Having your system on autopilot all the time isn’t optimal, but it’s better than NOT watering!

There are lots of good ways to set a drip irrigation system up. I’m going to explain my process step by step. Please know that it’s not the only “right” way.

First we bought a hose splitter, a backflow preventer, a pressure regulator, a timer, and a filter, and screwed them all together between the spigot and the adapter that connected it to the ½ distribution tubing:

That’s a lot of stuff! But it’s important for the usability, safety, and longevity of the system. Start up costs (both money and time) probably prevent a lot of people from installing drip irrigation. What’s worse, a lot of the supplies are plastic. In a class I took at Polyface Farms, another student asked Joel Salatin how he justifies the use of materials made from fossil fuels like plastic and gasoline. His answer was that for each situation, he asks himself: is there a less energy-intensive way to do this? That’s why he digs ponds to catch and store rainwater rather than relying on the aquifer, and places his ponds upslope of his fields so that gravity can move the water rather than a pump. But when it comes to actually delivering water to plants, he uses poly tubing, because it allows him to do more with less. He told our class, “there are virtuous and unvirtuous uses for everything. Drip irrigation seems like a virtuous use of plastic because it keeps us from wasting water.” Salatin’s not a perfect person, but I think his reasoning makes sense in this case.

Following the instructions in Curtis Stone’s The Urban Farmer, we outlined each of our main annual beds with a closed loop of ½ inch distribution tubing:

Then we ran two ¼ inch drip lines down the middle of each bed, attaching them on either end to the ½ inch distribution tubing. We inherited our drip lines from my grandfather, and they have an emitter every 12 inches. You can get lines with different spacing, or lines that are spongy like a soaker hose instead. That’s the backbone of the system. If you have a single garden area, it’s all you have to do! The couplers are easier to work if the tubing is warm, so I either do this on a hot sunny day, or I carry a thermos of hot water with me to soak the ends of the drip line in before I try to work with them.

Because our garden tends toward complexity (a polite word for chaos), we also ran ¼ inch tubing from the ½ inch distribution lines to any areas outside the plot that we knew would need extra water. This allows us to place emitters at the base of perennials that are just getting established, and mini-sprinklers in our raised beds.

At the end of each growing season, the ½ inch distribution tubing stays in place, but everything else is subject to change. If I need to temporarily remove ¼ inch tubing to prep a bed, I do so without a second thought, because it’s easy to put back. And on Mother’s Day each year, I double-check to make sure things are as they should be for the coming summer drought.

If you set a timer to operate your drip irrigation system automatically, I recommend setting it for as early in morning as you can stand to hear the water start running through the pipes. From Chan and Gill’s excellent book Better Vegetable Gardens the Chinese Way, page 67: “For as long as the Chinese vegetable growers can remember, they have always been getting up early in the morning to water their plants. They do not do this just because they like to, but because the way they understand the plants tells them that this is when the water is needed most.” They note that the plants need water to begin their day’s work of photosynthesis, and also that a blast of cold water can wash the leaves clean of bugs, and even of a light frost in early fall. (Your drip lines won’t be blasting any leaves with water, but that’s still good to remember for supplemental hand watering or fertigation.)

The first two years we gardened here, we were working with layers of cardboard, mulch, and arborist chips on top of sod. I knew it would take a lot of water to decompose that cardboard, and I knew that my plants would develop relatively shallow roots, so I set the system to water everything every morning. It allowed us to get good results even in marginal soil. I was thankful to put it on autopilot while we were distracted/exhausted by the birth of our son, and while I was busy nursing him and pulling wood chips out of his mouth.

As our soil has gotten deeper and richer in organic matter, it holds water better. For a few years, while our son toddled behind me and learned the names of our plants, I ran the system every other day or every third day. I supplemented the drip irrigation system by fertigating by hand with a diluted fish/kelp mixture by hand about once a week. I would always skip the drip irrigation for a day or two beforehand so that the plants would be ready to absorb as much as possible on “Stinky Fish Day” and get the maximum benefit. (“Stinky Fish Day” earned its name because I would absolutely reek by the time I came inside for breakfast, and be guaranteed time and space to take a shower by myself– a lovely side effect for any working parent.)

Last year, most parts of the garden only needed water once a week. After several years of rotational grazing by poultry, our soil’s fertility was through the roof, and I didn’t need to fertigate much other than dumping dirty duck water on my dahlias. So, I replaced “Stinky Fish Day” with “Drip Irrigation Day,” and only ran the system once a week. I did my spot watering by hand. (Spot watering is like spot cleaning for people who would rather do garden work than housework.)

How can I tell when to water? In the spring, when seeds are germinating and transplants are just getting established, I water almost every day that it doesn’t rain. In the summer, I usually garden barefoot, and although the top layer of mulch is dry to the touch, my feet can tell by its temperature and texture whether or not the soil beneath needs water. To double-check, I stick a finger in up to the second knuckle. If it’s dry that far down, I water. Some plants absorb a lot more water than others, so just because one area is dry doesn’t mean the whole garden needs a drink. It pays to walk every path every day and feel around. This year, we’re adding ball valves to our irrigation system so that I can toggle different areas on and off, pleasing both my thirsty cucumbers and my drought-tolerant tomatoes.

The great thing about a homemade drip irrigation system is that it can grow and change with you over time. When you’re starting out, it can be simple. As your soil (and your relationship with plants) becomes deeper and healthier, you can tweak it. Ecosystems get more complicated as they mature. Drip irrigation can support the emergence of complexity gradually and with grace.

Here Comes the Sun

by Peter Heffelfinger

posted July 20, 2020

With a full week of sun and warm weather in the forecast, the main garden chore becomes watering. The key is to irrigate as early in the morning as possible, allowing the plants to absorb a reservoir of moisture before the heat of the day. Cool morning temperatures reduce evaporation, with a greater percentage of the water being taken up by the plants. Early watering also avoids sun scald on the leaves, which can happen if irrigation is done later in the day when the sun is intense. Given the coming summer drought cycle, early in the day watering helps to conserve a vital resource.

Watering is key for new seedlings such as lettuce, coriander, fennel and dill, which can easily expire in the heat. For lettuce, which needs partial shade, I construct temporary shade coverings using the leftover black plastic see-through nursery trays supported by empty half-gallon plastic pots. It’s easy to water directly through the latticework of the trays. Plus, if you are transplanting starts for fall and winter, such as cabbages or leeks, they will need consistent watering until their root systems get established and can take the direct sun. Given our extended northern daylight hours, I cover new starts with either half or full gallon plastic pots for a day or two, and then move the pot adjacent to the plants to supply shade for a few more days against the sun’s rays. Think of it as a temporary sunscreen for tender plants.

My vegetable garden relies on an artesian well, which also supplies two households. Since the water supply is always on, with the overflow running year-round by the garden in a small ditch, I fill 55-gallon drums during off-peak hours to serve as garden reservoirs during the summer. One tank supplies a gravity hose to the hoop house; the other two I use for submerging watering cans to quickly fill them. I also do general watering by hose for large areas of brassicas, squash, corn and potatoes, or trellises of peas. Mostly though, to conserve water, I prefer to irrigate by hand so I can see exactly how much water is being absorbed by the soil, as well as checking on the condition of each plant. No droopy leaves.

Enjoy the sun, and keep the plants well hydrated.

Oregano Harvest

Now that the garlic is cleaned and curing in the shed, the next harvest on the list is my Greek oregano, the white-flowered variety as opposed to the more common purple type. I have a perennial patch that seeded itself in the rocky soil of a former driveway. I wait until the buds are just about to break into bloom before cutting the long stems, which I gather into large bunches hung up to dry in the pantry away from the sun. The fresh oregano bouquets always remind me of a favorite Greek grocery/delicatessen back East, which has large bunches of imported oregano, twigs included, tightly wrapped in cellophane. They hang from the ceiling overhead, just above the trays of baklava and the tubs of fresh pickled octopus.

When the harvested bunches are fully dry, I enclose each one inside a large brown paper bag, tie the top edge of the bag tightly around the exposed stem ends of the oregano and rehang. The bag keeps the dust off and captures any loose leaves that fall off the stems. I leave the bunches in the bags for use during the rest of the year; I find the dried leaves maintain their flavor reasonably well by being left on the stem. Plus, given our increasingly mild winters, my outdoor oregano stays green if I want to pick a fresh sprig. Best to have both indoor and outdoor sources, though. A double pantry.