Problems with sheet mulch/ farm update

We have installed lots of sheet mulches on the Lakewood farm. Sheet mulching involves laying an overlapping layer of cardboard to smother weeds, and then piling on a foot or more of organic matter, ideally weed free, and with a balanced ratio of nitrogen to carbon. There are lots of benefits to this: less weeds, more organic matter, and, after the first year, less work, since the beds are never tilled again. For more information, see this post.
However, we have discovered two potential problems with sheet mulching.
First of all, sheet mulch does NOT stop bindweed. Those long twisting roots easily wend their way around the cardboard and through every crack, to emerge triumphantly at the surface. However, nothing else really kills bindweed either, and sheet mulch at least makes bindweed easy to pull. And the sheet mulch killed off the grass, thistles, dandelions, mallow, and other weeds on our site fairly well.
The second problem is more serious. When we planted the tomatoes, we just opened a hole in the mulch, stuck the tomato in, and pushed the mulch back together. Some of the beds were full of a light, fluffy mixture of grass clippings and mulched leaves. We then got a lot of rain, and occasionally people would step on the beds (our paths are not that well defined.) The mulch compacted and sank. Soon the tomato root balls were sticking out of the mulch, where the peat in the potting mix acted like a wick to dry out the roots. The fact that the grass clippings were very porous did not help matters any. We first noticed the problem when a lot of the tomatoes looked sick, with curled and yellowing leaves on a hot day.
Hopefully, we have solved the problem by laying a layer of rough compost from the pile we built last year over the beds. This will cover the root balls and hold water.
So, if you want to build a sheet mulch:
Don’t expect it to kill bindweed,
Try to mix dried grass clippings with other, more compact and water retentive material,
Lay the mulch much thicker than you think necessary, and plant deeply,
Carefully pack mulch over the root balls of transplants,
And ideally, build the beds in the fall, so they can decompose and compact over the winter.
The tomatoes in our hugelkulture/ sheet mulch hybrids are doing splendidly so far. I will continue to report on the success or failure of our systems over the next year. And now we will know how to avoid this problem for the future.
We are almost done planting. We have also got a fence built on the perimeter of the property, set up plant supports, and done a lot of weed mowing on the site over the last few meetings.

 

Planting continues

We have now got tomatoes, peppers, eggplant, green beans, yard long beans, summer squash, zucchini, luffa gourds, pattypan squash, cucumbers, lettuce, potatoes, watermelon, cantaloupe, sunflowers, and some winter squash planted. We still need to plant dry beans and some more winter squash, and we will be done with the main season planting. Late, but hopefully not too late, if we get a reasonable autumn. We will be succession planting green beans, summer squash, cucumbers, and lettuce all summer. Cool weather crops will be planted in late summer.

Planting has begun!

Over the last few meetings, we got a lot done! We rented a rototiller, and broke up 1500 square feet, addition to the 1500 square feet of sheet mulch beds we already prepared.  We will plant into this area immediately, and mulch it latter. This will speed planting, since mulch supplies for our sheet mulching have been hard to get recently.
On Saturday, lots of members came out and planted 250 tomato plants. There are still some more to plant, but the biggest ones, which urgently needed to get into the ground, have all been planted. We prepared a lot of planting areas, and are almost done with the fencing project. We are digging big holes in unprepared grassy areas and filling them with manure. We will plant vining winter squash in these and let them help smother the weeds.
Next week our squash, melons, cucumbers, beans, lettuce, peppers, and eggplant will be planted. Because we got off to a slow start, we are waiting till late Summer to plant cool weather crops, except for lettuce. We have some heat tolerant strains of lettuce which we will be trying out.