Rainwater Harvesting Basics (1) Brad Lancaster video http://www.youtube.com/watch?v=2iQ-FBAmvBw
Jason Mendes wrote:Aloha! I have for the past three years been living in the tropics and making gardens and planting where soil is open or simply clearing away what's growing.. But now i am residing in the suburbs of Mesa, Arizona, where the backyard is all gravel.. I've done a couple of raised beds by pulling away the gravel and making a border with wood boards, but i am brainstorming ways to simply plant right on the gravel.. I do notice that many 'weeds' grow easily in the gravel. The ideas i have so far would be.. Layering cardboard and organic matter like grass clippings and kitchen compost, then possibly other soil/compost brought in. As i am writing this, i am thinking that raising the level of the soil could be a problem close to the actual house, because there is a foundation layer of cement, then up a few inches, stucco. So, has anyone done anything like this? Any ideas?
A few observations from living in the desert.
1. Cover the bare ground with what ever you have. If all you have is gravel and rock, use gravel, organic material accumulates over time and it keeps the fine soil from blowing away. The desert creates a crust that does that but building your home on land, they scrape off that crust and leave the fine stuff exposed to blow away in the 5 to 75 mph winds that spring up each year. Witness the dust storms in the Phoenix area that remind folks of the dust bowl years.
2. I don't know about your dirt in your back yard, but mine is nearly absent in organic matter. My dogs have been adding material over the years that they used my backyard as a toilet. But there is nearly nothing that holds onto water. I am now trying a combination of wood chips and straw built up in a pile over 3 foot deep. If you can get local tree services to dump off fresh grindings the mix of green and brown starts to break down, and when the winds come they don't blow away like the bark mulch does. The combination of grindings gives you a mix of coarse and fines that seems to stay where you put it. Wet it down periodically.
3. Sheet mulch. At least a 6 inch layer at a time, as you build up layers, you are putting something there that will actually hold onto water when you do get rain. You can leave the gravel there, don't bother scraping it off. If you look at the few standing plants that have leaves in the desert they are self mulching. There is almost always a 3 to 6 inch layer of "trash" under the branches that build up over time. You just want to do that on a larger scale.
4. Don't waste money on composter drums, they don't hold enough material for one, and the material they have is held up to dry out faster than it can actually work down. Building a pile against a corner of cinder block wall holds enough moisture that the pile actually works.
5. Learn how to catch and hold water for the few times you do get rain. Otherwise it runs off somewhere else. Find a way to channel and hold it so it soaks gradually into your soil. Build basins and gabions where needed. Be patient, you may have no rain for 7 to 10 months and then have 3 inches fall in 5 minutes time in your particular area and across the street will be completely dry. About once in every 5 to 10 years you will have up to 5 days that will sock it in and you will have rain that goes constantly but varies from spit to full on torrent.
6. Learn to use drip irrigation for the 10 months or so that you don't have any rain. Learn to use timers and check them regularly.
7. Containers, hold enough soil to give you a short term solution, but the containers don't really hold enough soil and water to be completely efficient without timers and drippers. You go away for a short vacation and the plants die. Also even UV blocked plastic seems to be good for only one year before the edges become brittle.
8. Green houses that face south for winter, that become shade houses during the summer. If you don't mind wasting energy you can even air condition your plants. Learn to create temporary shade for your temperate plants, yes I know that plant tag says full sunshine, but they meant someplace like Maine, not Las Vegas or Phoenix.
9. Basin gardens aka waffle gardens, a sort of sunken rather than raised beds, allow you to sink down to hold water long enough to soak in. Also the salts from irrigation or that are already in your soil tend to migrate up to the ridges of your basin. The ridges around the basin also provide some shade and wind shelter for tender young plants.
10. Map out your yard and learn where you might benefit from wind baffles to slow down the wind as it whips around your house. It is frustrating to plant ahead of the frost date and then have your tender young plants get whipped to death by the wind.
11. Learn the micro climate of your particular area. They tend to grow fast maturing varieties here because during the summer it gets so hot that some plants tend to drop their blossoms rather than set fruit unless you are willing to jump through hoops to provide the plants with what they need.
There might be more, but those come to mind for where I live.
dig in the grid, and swales to move the water around the yard. el-cheapo laser level works great for this.
There is a reason all the stuff out in the open desert is still alive, if it has rocks around the root area. they don't soak up the rain like biologicals, so more water gets to the roots in light rains, and the rocks cement the soil down, called desert pavement. if trying to garden without supplementary water, bury wood, put compost on top of it, then topsoil mixed with mulch back, newspaper, then layer that gravel back over, 2 inches if possible. use the dug out subsoil for the swales/rain ramps.
If you just want to get stuff growing right away, buy a couple bags of topsoil/organics, put long slit down back, flip it over where you want it, and cut in planting holes, right into the bag. If the holes aren't too big, it will hold water, to get stuff started, or grow wimpy northern plants. After a year or so, the plastic will break down, but by then the roots are into the subsoil, and the plant will prob make it.