No screening?

Hi guys! Newbie SFG questions here!

Curious.. what would happen if I put my SFG frame directly on top of bare soil, without having screening at the bottom of the frame? (Of course, I would have MM filling the frame, and the grid on top too) Why does Mel insist on screening (or Plywood) at the bottom? Are we simply trying to eliminate weeds from sprouting through? Or pests coming up into the mix?

Also.. and I know this has surely been talked about before, but.. if I do want to grow normal-sized carrots in my SFG.. how do I do it? It sounds like not having screening at the bottom then would make sense (at least for the carrot square?). Or wouldn't it?

In my yard, I need the screen to keep voles and moles out of the garden. They have a good time in the yard, and the last thing I want is for them to have a hey-day in my SFG! The screen won't keep the weeds out - they'll just grow right through the spaces in the screen. I put down a layer of cardboard beneath my box with the screen on top. So far, no weeds and no critters.

1airdoc wrote:In my yard, I need the screen to keep voles and moles out of the garden. They have a good time in the yard, and the last thing I want is for them to have a hey-day in my SFG! The screen won't keep the weeds out - they'll just grow right through the spaces in the screen. I put down a layer of cardboard beneath my box with the screen on top. So far, no weeds and no critters.

Neat! Thanks for the reply! I don't think I have any burrowing animals in my backyard here. Perhaps I could simply leave my SFG frames open-bottomed? I would think then that this would a) let me grow deep-rooted vegetables, and b) allow earthworms greater access into my squares.

On the negative side, I can imagine possibly some issues with existing weed seeds coming up through into my SFG. Plus, there is much greater a chance of the MM mixing with the standard soil in the backyard, which isn't a huge issue for me. If there are ground-based issues, such as insects, diseases, fungii, etc. then they would most-likely come through into my frames as well.

Hmm... perhaps I should leave the screening on some squares but not on some other ones.

Hi,
I put my boxes on top of the ground for a number of years. They did just fine. Every once in awhile when I replace a box or move a box I put down screen. I have a terrible problem with moles and voles. If you are worried about weed seeds, just put down a thick layer of newspaper or cardboard. It works great and the worms will munch through it if they want to. Happy gardening

Patty in Yorktown

ihayat wrote:Hi guys! Newbie SFG questions here!

Curious.. what would happen if I put my SFG frame directly on top of bare soil, without having screening at the bottom of the frame? (Of course, I would have MM filling the frame, and the grid on top too) Why does Mel insist on screening (or Plywood) at the bottom? Are we simply trying to eliminate weeds from sprouting through? Or pests coming up into the mix?

Also.. and I know this has surely been talked about before, but.. if I do want to grow normal-sized carrots in my SFG.. how do I do it? It sounds like not having screening at the bottom then would make sense (at least for the carrot square?). Or wouldn't it?

First I see this is your first post. Welcome! Hope you have read the book. Mel does not insist on putting bottoms or screen on the boxes. He recommends some sort of a barrier such as weed cloth or cardboard or even layers of newspaper to help keep weeds out and keep the MM seperate from the ground underneath. Wood bottoms are good for table top beds. Some sort of screening or wire bottoms are needed to keep out pests such as gophers. Before using wire on the bed bottoms I could not grow a garden. They got everything I planted last year. This year they got nothing!



My bed is a little deeper, about 10 inches and I grew carrots just fine but some do use high rise boxes. Mel talks about them on page 61.

I'd also toss in containment/retention and convenience in subsequent plantings of the box.



We don't have many burrowing pest where we are, but the screen keeps my mix in, slows the water drainage rate, keeps weeds out and limits the root length of the crop.



I'd hate to have to dig down a couple of feet to make sure I got all the roots out from a crop before replanting. With the mesh on the bottom, I always know where the bottom of the root ball is.



... but my opinion is based on using commercial-grade landscape fabric on the bottom of my boxes, so opinions/results may be differerent, based on what "screening" you use.

Thanks for the replies everyone!

I can better understand the reason for the screening material at the bottom of the frames. Although I'm still not sure how important knowing where the bottom of the roots for a given plant is. Could the screening (such as landscape fabric) keep out certain insects or diseases from entering the MM?

Does it really matter if the MM mixes a bit with the soil below? I suppose eventually it's bound to mix up with it, if the frame is bottomless.

Hmmm... ok, from what I can gather here, I'm now thinking of doing the following:

1. Construct three 4x4 frames
   
2. Lay them on top of the backyard where I want them
   
3. Use a spade to cut down into the grass sod
   
4. Instead of removing the grass, simply take it and flip it upside down into the ground
   
5. Add a couple of layers of B&W newspaper on top
   
6. Add MM on top of this into the frames until they are filled.
   

I think this method sounds quite easy and should allow me the convenience of growing even long-rooted items in relatively short frame heights. The newspapers should help biodegrade the grass, as well as keep weeds from coming up through the MM. As they break down, they should permit roots to poke through, as well as earthworms to migrate up.

Since I don't seem to have an issue with burrowing animals, I should be alright without bottoms. Perhaps I can put landscaping fabric under two of the frames and leave the third one bottomless for long-root plants?

Hmmm...

I made my garden the same way, except I removed the sod, turning it upside down and stacking it next to the compost pile. Busted sod and put the boxes right on the native soil, then filled boxes with Mel's Mix. I have only had trouble with one bed, and that is from tree roots coming up through and strangling the garden vegetable's roots, trying to get all the Mel's Mix. I think I will put down a piece of plywood in that bed this fall and refill the box. Otherwise I have had no trouble with plants coming up through, since I removed all the grass. I think the greatest benefit of this is the earth worms that migrate into my garden beds.

ihayat wrote: Could the screening (such as landscape fabric) keep out certain insects or diseases from entering the MM?

Doubtful my screening does much in that regard

Does it really matter if the MM mixes a bit with the soil below? I suppose eventually it's bound to mix up with it, if the frame is bottomless.

I imagine it completely depends on "whats underneath" in your specific location. For me, it's useless sand that couldn't sustain the most viable of plant types, much less something with the requirements of an edible crop.

Perhaps I can put landscaping fabric under two of the frames and leave the third one bottomless for long-root plants?

Hmmm...

Probably wouldn't do any harm, but some folks think the square foot of Mel's Mix provides all the nutrients a seasonal/annual crop will need. The idea behind SFG is more efficient growth in a smaller footprint, with less effort. Letting the root system get any bigger than it needs to be diverts resources from the important stuff (fruits/veggies) {opinion}.

Additionally, letting the roots go into "unknown territory" may expose them "the unknown things that lurk in unknown territory" (like nematodes and other root-critters) , which is kinda counter-intuitive to the benefits of containerized gardening.

However, if your growing enduring, multi-year or perrenial crops in yr SFG, then the concept of longer/larger root base would have a lot of merit.

Like most things, it all depends on what works for your personal situation/goals.

I doubt that cutting the sod out and flipping it over is necessary. If you just cover the grass with a good layer of newspaper or cardboard, that should do the trick and it will save you a lot of backbreaking labor. I didn't have a single weed crop up in my garden after doing that (except for where my son blew grass clippings into the SFG from the yard while mowing!).

This year I put in several new boxes, and cardboarded some, and just laid others on top of the grass. I was hoping for maximum penetration by earthworms, so no screening for me.
I have just about the same amount of grass growing up into the beds, which is very little. It's all around the edges, where the grass in the aisles is growing under the boards and into the beds. Vinegar poured along the outside of the boards kills it off pretty well. Helps with the slugs, too.
My broccoli that I just pulled had beautiful roots, the same depth of the MM. Same with the peas. Yes, a very late, cool summer for us in the PNW.