A short while ago I was writing about drought and the effects of overly-dry conditions. Since then the monsoon season began early and rain became a common occurrence. Last week Colorado Springs set a new record for most rainfall in one day; 2.3 inches fell in the afternoon. Just when I was dealing with irrigation issues to try and keep my plants watered, I suddenly had to deal with drainage issues to try and keep my plants from drowning.
My latest dilemma arose due to saturated soil. As part of my analysis of the soil in my vegetable garden, I realized I have an expansive layer of clay about a foot down. To overcome this problem I brought in a few truckloads of amended soil. That raised the surface level to offer plant roots more room to grow before encountering the clay. In dry conditions that solution works well but after days of torrential rain the upper soil is soaked and drainage becomes virtually nonexistent when the water hits the clay level.
In my numerous raised beds, I brought in new soil and amended it well. As I've described previously, compost and organic matter act as little sponges to absorb water and help keep the soil moist. That reduces the need for daily watering during dry days. During the monsoon season the excessive rain and vertical sides on the beds create a bathtub effect that can hold in the water and the organic sponges keep it there.
Regardless of how much time was spent designing channels and troughs to collect and divert water for dry days, it's now time to dig through the little dirt walls and allow the water to drain away from the garden. Once soil is saturated the only thing to do is to reduce the addition of more water.
Eventually sun and wind will dry out the garden and things can return to normal. You can use that as part of your recovery plan. Mulch works very well to keep the soil surface from drying out. During extreme water events you may need to remove mulch to give the soil extra opportunity to dry. Expose as much surface area as possible to the air.
I use straw as a mulch in many areas. Extra straw in the low spots will absorb rain. If I pull out the soggy straw after a strong storm, I can at least keep that amount of water from adding to the drainage concerns.
If you cover your raised beds with plastic during cold weather, it may be time to bring the plastic back out and cover the beds during wet weather. Watch the forecast and put a lid on the bathtub to keep it from filling.
Identify points and places where the water pooling is worst. Just as a pot needs drainage holes, you may need to create drainage in areas of your garden you hadn't anticipated. Drilled holes in a raised bed, overflow hoses, and alternate water channels can divert excess water. You may be able to make some of those corrections during the rain storm and you may have to wait until the soil has dried afterward. Either way act to keep the problems from returning.
Some things should go without saying, but I'll say them anyway. If your irrigation is on an automatic timer turn it off after a day or two of excessive rain. You don't want to add to the problem by overlooking that. Before you begin watering again don't assume the roots are good because the surface is dry; make a physical check of the moisture level a few inches deep.
If you're planning a new bed in the future or redoing an old one and plan to bring in custom soil, opt for one that has a good sand component. Sand drains well and can help minimize drainage issues. Organic soil amendments are always a good idea and ensuring clay soil is amended well can improve its drainage.
We've had a few dry days and my garden has recovered. But there's a solid chance of more rain today and for the next few afternoons. I now have drainage channels, plastic ready to pull over the hoops on the raised beds, reduced mulch in some spots, and extra straw in others. I look forward to the rain because it cuts down on my need for supplemental watering and now I don't need to be as concerned about drowning my plants.