Rainwater Harvesting Notes

Rainwater harvesting notes, prompted by someone’s post in a Florida mainstream gardening group, about the current drought and people’s resulting increases in water bills:

• I use rainwater harvested from my roof. Carrying water all over the yard to the plants every day in this drought has been exhausting and time-consuming, but at least the water is free!!

• I always wonder why rainbarrels are not more popular here in Florida. I would never want to do without them! I have a total of about 500 gallons of rainwater harvesting/storage capacity.

• I have 500 gallons water capacity. I just put the barrels and troughs under my roof line to catch the water. A 1,000sf roof can catch up to about 600gal of water in a 1-inch rain event!!!! (Actually I think the rainwater calculator I use at a website called watercache.com says 623.)

I scoop the water out by hand with a watering can and carry it out to the plants all around the yard.

• Of course, watering needs will vary from place to place, and by type of garden.

The main focus of my yard is shade, water conservation, soil-building, native plants, and biodiversity. I have many wild edible so-called “weeds” growing in my yard that are highly nutritious and need much less water than cultivar veggies. I also have baby fruit trees and a few cultivated veggies.

My existing 500-gal setup easily gets me through the dry season in a normal year. As the “hot dry windows” in fall and spring seem to be expanding, it gets to be more of a challenge. I am planning on adding another 500 gal to my household system. It’s a work in progress.

Another key component of rainwater collection, besides barrels/troughs, is the ground itself. Minimize bare soil; turn the ground itself into a sponge by adding mulch, plants, etc.

Brad Lancaster, rainwater harvesting expert based in Tucson AZ, has great videos and I recommend his book “Rainwater Harvesting for Drylands” to everyone in Florida [and everywhere else, for those of you outside Florida who are reading this], since our landscaping and development practices are basically turning Florida into a desert.

Also – not all gardens are created equal. In Florida, the most successful food-gardeners I know are growing food in dappled shade — creating multi-story food forests, rather than unshaded, rectangular plots with veggies in rows. The latter require huge amounts of water and still struggle in the Florida sun.

Suggestion for anyone interested in learning more: check out permaculture / food forests.

Tucson AZ gets 11 inches of rain a year. In most of Florida we historically get over 45. I highly recommend Brad’s book to everyone. And highly recommend Brad’s video “Planting the Rain to Grow Abundance.” This 18-minute video is a great investment of any gardener/homesteader/concerned environmentalist’s time today. He has numerous other videos as well.

Another super resource: Watercache rainwater harvesting calculator

• (In response to someone who said her county is on a total ban, and they can’t even water one day a week): Where I live, there are certain exemptions from the watering ban, such as watering a food-garden or watering by hand (with hose, or watering-can).

Since I furthermore water with rainwater (that I caught off my roof during rainy times), I am not subject to the watering ban and am able to water daily. I water different plants in the yard in rotation. My kumquat tree and lemon tree each got the big 2-gallon watering can yesterday. This morning I watered the plumeria which provides dappled shade for Okinawa spinach and other summer greens (and also provides beauty for the neighbors and people who walk by).

I have been using 15 to 20 gallons of water each day, in rotation, on the plants in my yard to try to patch them through this drought. As the “dry window” times in fall and spring seem to be getting longer each year, I have started dreading what a rainless June might look like in Florida; I hope we don’t have to find out. (Actually we have had a total of almost an inch so far this month, but we are very far behind our normal for the year, as is most of the rest of the state from what I hear.)