Many of us know how devastating droughts can be to gardening, but rarely do we talk about how dangerous excessive rainfall can be. Tomato plants can drown, seeds can be washed away, mold and fungus can take over, and inches of topsoil can be be piled in the corner of your garden, leaving only gullies behind. Even if you don’t live in a low lying area, large amounts of rain can painfully disrupt your growing season. But there are ways you can prevent and prepare for damage from heavy rainfall, and also ways to train soil to take on more moisture.
1. Consider Garden Placement & Soil Type
The ideal garden to manage rain is flat with good drainage and sunlight. Unfortunately, such a scenario is not always available. So first, it’s important to look at soil types. Heavy clay will hold water longer than sandy soils, and thus might not let water pass through as quickly. Loamy and silty soils are preferred because they are somewhere in the middle, holding water for longer in dry periods, but also allowing for drainage. If you have a choice, avoid clay soils if standing water will be an issue. Also avoid flood plains where possible. If you can have your garden on higher ground, that is optimal, and if the garden must be on a hillside, consider pointing your paths downhill, so the water will drain off as it hits the compacted paths instead of standing.
2. Use Natural & Artificial Drainage
If your only garden option is at a high risk for standing water during and after rain, consider some drainage options. The first is amending your soil with sand to balance out the drainage. For small gardens, this might be reasonable work, whereas for very large gardens it might be a big endeavor. Also, it will help only so much. You will probably need to implement at least one other safeguard.
The second option is to add ditches around the garden to divert water away from crops. You can dig these with a trencher and fill them with a plastic lining, or just leave them as dirt ditches that point away from the garden.
Third, and perhaps most invasive, are drainage tiles. Installing drainage tiles (which are essentially perforated pipes or gutters) beneath your garden can help mitigate the risk of standing water from rain, increasing the drainage capacity. Research this well, as it will be a fairly large task, and you must consider the pipes before tilling or plowing. Of course, drainage tiles can also be placed uphill of, or around, your garden as well to mitigate excessive rainfall, but they should always be placed downhill in a way that sufficiently drains the water away from your crops.
Raising your beds will, at the very least, reduce the amount of time plants have to sit in standing water after heavy rain. Raised beds also dry out faster, which can be good after an excessive rain event, but obviously bad during a drought. Weigh the odds of each, as they can both be disastrous, but for the most part it is easier to add water to a garden than it is to remove it.
4. Boost The Soil’s Organic Matter
One excellent way to avoid large puddles of standing water because of rain is to boost the soil organic matter of your garden. Organic matter absorbs moisture and helps evenly distribute rainfall. A healthy garden full of large quantities of organic matter can take on considerably more water than one low in it. To add organic matter, consider mulching more (described below), adding peat moss (with lime, as peat moss is acidic), or adding worm castings, which work to help spread out water. In fact, having more organic matter brings in more earthworms, which in turn create more worm castings––an easy and natural system of water management.
5. Create Mulching Paths
Adding wood chips, straw, or hay to your garden paths is an excellent way to not only add organic matter (as described above), but also to have a carbonaceous material in the garden that can absorb some water during and after rain. Because wood is fairly water-resistant, straw works better at first, though as wood chips break down they can better absorb and mitigate standing water. And again, the organic matter will help, and worms will love the cover. I say use a combination.
6. Leave No Soil Bare
Lastly, excess water can be mitigated by mulching around plants to add organic matter and absorptive material, but also by leaving your paths in clover or grass. You can mow these paths regularly, and the roots of the plants of will take up excess water. In fact, legumes such as clover will also add nitrogen to the soil, helping to feed the plants. Turning excess rain into food for your plants is good.