One of my favorite sayings reminds us that, “Too much of a good thing is a bad thing.” This is especially true when it comes to rain.
As most of us learned back in school, rain occurs when water evaporates from the Earth’s surface, condenses into clouds, and then falls back to Earth. In doing so, this water cycle moves minerals, chemicals, dust, seeds, plants, and even insects around.
Now, after years of drought, the Bay Area is happy to receive rain, any rain, all the rain it can get. Thirsty lawns, marginally watered ornamentals, and gardens of every size, shape, and style absorb the rain as fast as they can, except for when they can’t - and that can be a problem.
As rain falls on your garden and landscape, one of the first things that happens is the dust is washed off the leaves. This is good for the plants because it allows them to perform photosynthesis more efficiently and it makes the neighborhood less desirable to spider mites. That dust-filled water falls to the ground where it is probably absorbed right away. In some cases, the ground is so dry that it becomes hydrophobic. Hydrophobic soil actually repels water, causing run-off and erosion.
Assuming your soil can absorb the rain water, gravity and surface tension will pull the water deeper into the soil, hydrating roots at various soil levels, until it reaches bedrock or an underground waterway. If the water cannot keep moving away, it will pool, creating mud bogs that can drown your plants. If it can move away, it will leach nutrients and chemicals with it, which is why it is so important to avoid using excessive fertilizers and pesticides.
When really heavy rain hits many parts of California, we also have to watch out for flash floods. Creek beds that have been dry for so long that no one remembers when they were ever wet suddenly play host to a crashing, raging wall of water, seemingly out of nowhere. That’s not very likely, here in San Jose, but it can happen in flatlands surrounding the hills. More often, rain causes car accidents because so many people forget about the oil on the road (and their good manners), but I digress.
I collect rain water from the roof of my house with three rain barrels. Of course, these 65-gallon rain barrels fill up surprisingly fast, so I have to connect a hose to the spigot at the base and redirect the excess somewhere else, usually to the lawn or, if it’s been raining a lot, to a swale near my fence. I recently learned about rain gardens and I may install one someone in the landscape. You’ve already seen rain gardens, you probably just didn’t know it. Rain gardens are sunken areas with native perennials, shrubs and flowers planted around the depression. Most of the time, rain gardens are dry. When it rains heavily, the sunken area fills up with rain. Because there are so many plants in a rain garden, the water is usually gone within 12 to 48 hours, eliminating concerns about mosquitoes. According to The Groundwater Foundation, rain gardens allow 30% more water to soak into the ground, removing 90% of the nutrients and 80% of the sediments from the water, compared to a traditional lawn. [Looks like I’m going to have to do a bit more research on rain gardens!]
So, if you are dealing with rain, keep a look out for soggy areas that need better drainage and enjoy the time you would have spent watering by doing something relaxing indoors instead!
How do you handle too much rain in your garden?
You can grow a surprising amount of food in your own yard. Ask me how!