[Community_garden] How/whether to prevent leaching into sandy soil

[yarrow at sfo.com]

At 2:29 PM -0500 9/6/07, Ken Hargesheimer wrote:
>No liners, etc.  Do three things:
>1. Add organic matter
>2. Add organic matter
>3. Add organic matter
>Add it by bringing it to the garden and/or use green manure/cover crops.

Ditto. You will have to keep adding more every season. The purpose of 
adding organic matter is to nurture the soil food web, which, in 
turn, takes care of feeding the plants. So you *want" the organics to 
trickle down into the soil.

The simplest and easiest way to improve any soil is to add several 
inches of mulch. Even better, pile up to a foot or so of mixed 
organic matter over the winter in the beds.

You can get free organic matter from many sources. Here are a few:

-- free truckloads of chipped branches from tree trimmers. Look in 
the yellow pages and call around until you find one that will do 
this. If it's mostly wood chips from big branches, use it for paths. 
If it's mostly greens and smaller twigs, pile it on the beds over the 
winter, or use it as a mulch on the beds during the growing season.

-- free used coffee grounds from coffee shops. Starbucks's corporate 
policy is to give away "grounds for gardens." It has a neutral pH and 
is a good nitrogen source, so can be incorporated directly into the 
soil, even a week or so before planting. If you have enough people 
collecting it daily from their local coffee shops, this can easily be 
the only organic matter you need, since tons of it are produced daily.

-- free leaves from deciduous trees, collected from neighbors; find 
out if community greenwaste will deliver truckloads.

-- free vegetable waste from grocery stores. Some places will let you 
have as much as you can haul away; others will dump it into locked 
dumpsters, destined for the landfill, and not let anyone use it. Best 
used in closed compost bins or, in piles or "lasagna gardening" 
layers, covered with several inches of mulch or straw.

-- straw bales, pumpkins, and corn stalks used as 
halloween/thanksgiving/fall  decorations, then discarded -- from 
either homes or businesses. Contact them when you see the displays, 
and offer to cart them away after the holiday.

-- horse manure from local riding schools, they may be willing to 
deliver a truckload as it accumulates. Some of these places even have 
a big pile they don't know what to do with and would be delighted to 
find someone who's willing to haul it away. It does need to be 
composted (or left on the beds to compost over the winter) before 
growing food in it, though you can grow cover crops in it.

(I piled 8-12 inches of horse manure and bedding [wood shavings] onto 
my good soil last fall, then in the spring pulled aside enough to 
fill a basin with 5 gallons of homemade compost, and planted one 
tomato plant in each "basin." Thus, the manure/bedding is now serving 
as a summer mulch as well as adding nutrients as it breaks down.)