Sunday, July 20, 2014

The hazards of driplines

We finished converting our garden to driplines this year. This means no overhead sprinklers. We're using about 20 to 30% less water (an important thing, in a desert) and the plants are doing fabulous.

Except...some of them aren't.

A month or so ago my winter squash wilted. Just a little, and I wasn't concerned because it was really hot (into the hundreds) and they were getting plenty of water.

The next day the whole plant was dead. Of course it took a while before the green leached out of it (we currently have a winter squash skeleton sprawled over a quarter of the garden) but it was really that quick. No sign of wilt prior. We checked the leaves for insect damage and found nothing. No white scum or other signs of disease. Completely fine one day, and gone the next.

It wasn't gradual, as I would expect with most squash pests, and it was the whole plant at the same time. Most squash pests will kill one part of the plant, or the leaves will die and the fruit continue to grow, etc. This was sudden, and complete.

We did what we could to save it. Shaded the root ball during the day, extra water, special fertilizer, and we put soil over the root nodes in the hope that it would put down more roots.

Too late.

Since nothing else in the garden was affected, we let it go. A fluke, right?

Last week one of our zucchini showed a hint of wilt. The next morning...

This time we were proactive. We took all the fruit and blossoms off it first thing, shaded the whole plant and put soil over the nodes. It's currently struggling.

When that happened I went into detective mode. I dug up the root ball of the winter squash. Normally these things are two to three feet across, with a tap root that goes four feet into the ground. Getting them out in the fall is a major chore. The tap root was maybe six inches long, with a handful of spindly little roots sprawling limply about six inches from it.

No wonder the thing died! With 200 feet of runners, dozens of blossoms and a dozen developing fruit, it simply didn't have the root capacity necessary!

It's possible that something ate the root—we do have gophers—but as I said, we finished up the drip lines this year. I was careful to space the plants right under the driplines, we've been watering twice a day (10 minutes, morning and evening) and to add insult to injury I surrounded all the plants with 4 to 6 inches of mulch to keep weeds down. Evaporation is lower.

I took good care of my plants—too good. They didn't have to stretch to get what they needed, so they didn't have the root mass necessary when they started producing. When we pulled the fruit off the sick zucchini, it had five good sized zucchini and three starting. The winter squash had about the same. Too much for those tiny, shriveled roots to support.

Last week we dropped watering back to once a day. We'll drop back to once every other day if necessary. The zucchini plant is starting to come back—maybe. It's poking a few new leaves up. We'll see if it survives, but you can bet that next year I won't be so careful.

I'll plant between the drip rows so the plants have to strain for the water, and water less.

It makes an interesting parallel with taking good care of human beings, but that's a rant for another time.

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