Water is precious these days, so put it in the right spots

Oregon is known as a wet place — and that is true for nine months of the year. (This year, not so much.) But during the heart of the growing season here, we often get less than 1 inch of rain, while your garden will need 12 inches or more. Before I go into how, or if, you get all that water onto your vegetable patch, let’s talk a little more about our climate.

In most of the country, the three warmest months of the year are June, July and August. In the Willamette Valley, it is July, August and September. The reason? The Pacific Ocean. All that water warms up more slowly than the land does around, say, Iowa. On the Oregon coast, the three warmest months are August, September and October. What this means for us is that the summer garden season starts a month later and lasts a month longer for us — and that you have more time to get started.

Now let’s get back to watering. The worst way to water is with an overhead sprinkler, although it’s also the easiest in the short term. Overhead watering, especially during the day, loses water to evaporation, leaves plants and vegetables wet and more prone to disease, delivers the same amount of water to rapidly growing lettuce as it does to just sprouting cabbage, and puts weed-nourishing water into the spaces between your plants. If you do overhead watering, put a few cans or irrigation gauges out in your garden when you water, so you know how much you are applying.

Drip irrigation takes a little more time to set up initially, but once it’s in, it makes watering easy — on your schedule or with a timer for vacation days. Drip irrigation uses ¼-inch tubes with holes for crops like corn and lettuce, or individual drippers placed at the base of a plant like a tomato or pepper. Garden centers and internet videos can also explain how the systems work. Soaker hoses are not drip irrigation, but they are better than overhead watering. 

Another simple way to water is by hand. Being out in the garden will give you first-hand information on the water needs of your plants. Hand watering lets you put the water on the ground, not on the plant’s leaves. Even if you are using drip irrigation or an overhead sprinkler, some spot hand watering is always necessary for the best plant growth. The drippers set on a small zucchini plant may be overwhelmed when the plant gets into full two-a-day squash production.

To really know how well your water application is working, you have to dig down into the soil once or twice during the season. Not right at the roots, but nearby. Watering with a hose often dampens just the very top inch of soil — or less. Dry soil is surprisingly hydrophobic or water-repelling. 

Dig down after you have given your plot a good soaking and you might be surprised by how little the water has penetrated. The two-hour drip cycle will get water down to the roots of your plants.

A layer of mulch around your plants is a great way to ensure that the water you put on your plants stays available rather than evaporating. Leaves from last year’s leaf pile are great. You can also use cardboard, newspapers or grass clippings as long as you haven’t sprayed weed and feed on your lawn. (The herbicide in weed and feed will kill most garden plants.)

And of course, the amount of water your garden needs depends on the weather and where your crops are in their growth cycle. During a hot spell, you may need to water three times in a week, while cool, cloudy or wet weather will lead to lower water needs for your plants. Local utility Eugene Water & Electric Board provides evapotranspiration information and recommendations on how much water to apply to lawns and gardens.

Here’s an idea that few people will try, but it is food for thought — and stomach — without any watering at all. Dryland farming relies solely on rainfall. It works well here with winter crops, such as greens, broccoli and fava beans. But I know a couple of folks who plant their summer garden, lay down a thick layer of mulch, and harvest most of their crops, including tomatoes, peppers, and squash, by mid-August. The yield is smaller, but the taste is better.

Finally, I have to mention your lawn, which is often the largest water user in your home. Lawns here will go dormant if you don’t water them, and then they spring back to green life when the fall rains arrive. Consider reducing the amount of water your lawn gets, or letting some sections go dormant, while only areas that get greater use are kept green.