When I switched from gardening in the earth to raised beds there were 2 primary reasons for it. First, I live in the north where spring soil is cold and usually very wet (clay). It made spring planting difficult. Second, the weeds. OMG the weeds. Most of my garden time was spent pulling or hoeing weeds which I didn't enjoy.

So, going from an earth garden to raised beds I looked for ways to not lose out on the number of plants I could grow or the harvest I could get.

I was very much influenced by Square Foot Gardening and built my raised beds using Mel's mix. My beds are open to the earth though and the clay soil under them is very fertilize.

I was never particularly impressed with plant growth purely from the compost. It was fine except there was never enough nitrogen to optimally meet the plant needs. I am sure it can be done, but one would have to be very choosy about the compost to ensure it can provide adequate N. I then began adding soybean meal as an N source. This has worked just fine. It's also what I use as a lawn fertilizer.

So, can Mel's mix work without additional fertilizer? Yes, but it needs to be top notch, nutrient containing compost, particularly for N.

How do the raised bed plants perform compared to in ground plants? Very favorably.

Spring plants always do better than the in ground did simply because I can plant them at the proper time and not have to deal with a nearly frozen, sopping wet clay muck mess. Warm season plants also thrive, probably due to the extra warmth the bed provides and the better drainage. The relative lack of competition from weeds is also an advantage.

Now, would I recommend Mel's mix to others? Yes, but I think raised bed gardening in general is advantageous, particularly for those of us in wet or cold climates and those who aren't in love with weeding ;)

I have considered adding some soil to the mix as it shrinks in volume over each season quite a lot and I wouldn't mind a little more water retention in the hot/dry summer. In other words I think it's a good mix, at least for my climate, but I don't consider it the be all end all.

Mel's mix is a very expensive way to achieve a rich soil, imo.

It's a great container mix, but people spend a LOT of money building outdoor beds with the stuff.

1/3rd peat and 1/3rd vermiculite is an expensive counter-productive mess even if it works. 2/3rd of the soil is guarenteed to be devoid of nutrients with this mix relying on pores in the vermiculite and whatever nutrient-soaked-water the peat can take on.

On the lighter side, it'll be easy to tend/turn this soil over the years. The cost of it all is a determent to me.

The initial cost is quite high, no doubt about it. But you did hit on something I really love about this in a raised bed. It's firm enough to provide adequate plant anchorage, but it is also very soft/loose.

I don't use shovels for turning the soil to mix something in nor do I use one to put plants or seeds in.

For plants I just scoop with my hand and for seeds I just poke with my finger. It's wonderful and one of the reasons I have delayed adding any actual soil to the mix.

Weeding is pretty easy as well. Unless they get established enough to put roots into the clay soil under the bed all of them can be hand pulled with little effort and come out with the complete root system intact versus breaking off in the soil only to regrow.

I assume you know there is a Sq. Foot gardening forum here? They can best give you info on comparing Mel's Mix to other mixes as I know many on the forum use modification of the basic mix - get's discussed regularly there.

My own square foot beds started out with the basic Mel's Mix and did well though I never lined the beds or blocked root access to the soil below. But over the years they were quickly modified to include much more compost (but no additional peat) as well as bark fines and layers of hay/shredded leaf mulches that get tilled in each year. So the organic matter levels in my beds are more in the 50/50 range now.

Mel's Mix isn't "unfertilized" as it is 1/3 compost, one of the best "fertilizers" there is but I have used supplemental feedings over the years as needed per plant appearance. Intensive planting uses nutrients quickly, some crops much more quickly than others, so supplemental feedings of compost and compost tea are very beneficial IMO.

Dave

Ok, I need 15 lashes with a wet noodle. I actually meant to post this on the SF forum but was in a hurry and didn't check to see where I was. Sorry about that. Is there a polite and proper way to correct this error on my part?

Thanks for the wonderful info you have given me. My beds are sort of "semi-SF-gardens" in that they aren't exactly up to Mel's measurements and one isn't "square" but designed to fit the space. Also, they are filled with the already rich (fetile & well amended with compost) soil from the original beds with added very course textured peat moss leftover from another project. I also added Plant-tone at the label recommended rate. The veggies in them are growing well and I'm happy with the beds so far.

I guess my main concern in true SF gardens without access to the soil beneath is the possibility of a lack of some nutrients the soil provides that may not be present in the mix. We're still learning more and more about the soil and microherd and nutrients and such. Plants were adapted to growing in soil and I worry that it's difficult to match that with "soilless" mixes. (Yes, I know there can be trace amounts of soil in compost but perhaps it's not enough to compensate???)

I'm asking because I teach a class on small space vegetable gardening and I'm worried that I may be leading the students astray when I suggest box-type raised beds or containers with some mix that's similar to Mel's but that don't have access to the native soils. Maybe I should ask this on the container forum!

Sandy

There is absolutely no reason at all to close up a raised bed to block access to the soil underneath unless your goal is to restrict root growth.

It can cause a lot of problems with soil health.

I'm asking because I teach a class on small space vegetable gardening and I'm worried that I may be leading the students astray when I suggest box-type raised beds or containers with some mix that's similar to Mel's but that don't have access to the native soils.

If the boxes have to be closed to the soil (and there are many reasons to do this such as gardening on cement or raising the bed high enough for wheelchair access or for those who can't kneel,bend over etc) then I would skip Mel's idea of compost only and treat them as large, shallow containers as the drainage properties of a closed bottom system are much, much, much different than with an open to the earth system.

You might enjoy the discussion that would take place by bringing this up on the container forum.

It may seem odd, but Mel's mix offers superb drainage as a mix for raised beds, but fairly poor drainage in a container. Head over to the container forum and we can explain why this is ;)

How on earth can you have drainage problems with anything 1/3rd vermiculite and 1/3rd peat?

I use various mixes of peat, perlite or vermicultie, and pine bark in various applications in soiless mediums.

I guess if you're using a mucky compost or heavy organic soil it can really screw with the moisture, though.

Thank yall very much. Red