lakeside-seminar-sept-16Sheri and I just finished teaching the last of the San Diego Sustainable Landscape classes down in Lakeside. It’s a bittersweet moment – we love teaching that class, so it’s sad they are all over. But we have plans, so watch this space!

Meanwhile, people always have more questions, and we are really happy to answer!


Thanks again for the great class on Saturday. I have completely changed my design plans based on what we learned and am going to take the San Diego Sustainable Landscapes approach rather than the weed cloth/rock/DG approach.


One question:  Can we saw cut through a driveway to get the rain gutter runoff diverted to a new swale that we’ll build? We’ve calculated the amount of cubic feet of roof will generate but I can’t find a formula for how big the swale should be to accommodate that water. Is there some standard formula for that?


Thanks for any info you can provide and I look forward to my a beautiful, healthy yard that’s water conscious and sustainable.


Yes, you can saw cut through the driveway to move water away from house into landscape. We did this for a workshop in City Heights back in June and used a local company called Cut N Core (858) 560-6627


The calculation for the size of the swale is


the number of gallons divided by 7.48 = the number of cubic foot you need for the water


So, if its a 1″ rain event on 1000 square foot of roof, you can expect to capture 620 gallons

If we divide 620 gallons by 7.48 we get 82.88, call it 83 cubic foot.

You would be looking at an area that is roughly 10’x8′ or 9’x9′ or 40’x2′


I’m getting really skeptical comments from my family & friends about not using weed cloth. I’ve removed fescue grass, very healthy grass by the way with few weeds, but what’s to keep the grass/weeds from growing back if I’m not using weed cloth or DG?


My husband says we can work compost into the soil with the tractor (it an 8,000 sq ft area) but wouldn’t that only encourage every living thing to want to pop back up? He said he doesn’t want to go from mowing/edging every weekend to pulling weeds. Good question!


I’ve got him sold on the idea of catching our own water, now how do I convince him to keep the soil healthy by not compacting it?

weeds grow through weed barrierAnswer:

Weed cloth – if I could get a dollar for every installation of weed cloth that I’ve seen with weeds growing through it, I’d be rich! Sheri used weed cloth at her house- her gardener convinced her it was the right thing to do. 6-8 months later I came over and saw weeds growing right through it.


Weed cloth also stops oxygen and water from getting to the soil- key parts of OWL. And it collects blown dirt which allows weed seeds to root and grow. When you then try to pull them you end up pulling up the weed cloth with them. Finally, I used to use it when I was contracting and we could never keep it properly covered with mulch. There was always an edge or corner showing.


DG is ok for walkways but once you add stabilizers it becomes pretty impermeable. So much so that the new turf removal incentives will subtract any square footage covered with DG from the total of turf removed, meaning you won’t get credit for those areas.


The sheet mulch process has two parts to help stop weeds growing back. The first is the physical barrier of the cardboard or paper. This starves any weeds that do remain of light, so they die and decompose. The second is that soil that has some fungal activity (that 4″-6″ of mulch) is a natural deterrent to weeds. Weeds much prefer soil that is “new” with very little organic matter, just like annuals and veggies. In nature we would have to wait 100s of years for soil to go through this development, with weeds growing and dying many times over to build up the organic matter. The sheet mulching accelerates that process.


And talking of fungal activity – tilling soil breaks any fungal network up so we don’t recommend that. You will turn up weed seeds and push the soil development backwards towards the bacterially dominated end of the spectrum. This is why so many farmers are moving to ‘no till’ methods.


I hear the concerns about work in the new garden but all I can tell you is that my personal experience with my own yards, my experience with my clients’ yards and the studies (Santa Monica garden/garden) show that these sustainable landscapes take a fraction of the maintenance of a traditional lawn based landscape. There will be work up front but given time the self sustaining system will kick in and you will get to enjoy being in your yard rather than having to work in it.

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Diane Downey and Sheri Menelli specialize in earth-friendly landscaping practices, including vegetable gardening, rainwater capture, soil health, native plants, and efficient irrigation. Diane is a professional landscape designer with over 10 years’ experience, and Sheri is a certified permaculture designer with a six-year-old food forest in her backyard. Combined, they have over two decades of teaching experience. Their classes are taught to the public in the classroom, in the field, and via one-on-one garden coaching sessions.
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