diagnosing problems with raised container bed soil

Hi All!

I am relatively new to the world of permaculture (and gardening in general). Last season (spring), I built several large raised beds (3ft x 6 ft x 2 ft) that are elevated from the ground. I ordered 6 cubic yards of what I thought would be great soil from a local soil company and had it delivered by dump truck. This was obviously going to be more than I needed for the raised beds, but I thought it best to have more great soil than less.

The soil was called "nursery mix" and they tell me it is comprised of 50% nitro humus, 20% compost, 20% wood fines, 10% sand. The wood fines especially make it a very "coarse" feeling soil. I have attached a photo of the dry soil.

I filled the raised beds and several large pots with the soil and planted several summer veggies (tomatoes, peppers, melons, summer squash, scarlet runner beans, green beans) — some from seed, some from starts which I started from seed indoors.

Initially, things looked good, but very quickly, as the summer grew hotter, all of the plants grown in these beds suffered. I watered daily. But the plants browned easily, seemed more susceptible to pests, and were quite spindly. I tried various organic fertilizers, but none of the plants ever developed as I would expect. Then I planted a couple starts of tomatoes and peppers in new pots (this time filled with a potting mix amended with homemade compost). These plants have all grown quickly, with lush foliage, and healthy fruit set. The only distinct difference is the soil.

SO... I am trying to assess what may be going wrong with the soil I purchased. My best guess is that the soil is not retaining moisture and when I water, most is just running down and out through the bottom of the beds. I am watering by hand with a hose fitted with a sprayer.

Does anyone have a guess as to what might be happening? And any suggestions for ways to amend this container soil to improve the chances of my fall vegetables planted in the same containers?

Also, I have several cubic yards of the soil left. What suggestions do you have for it's best use, if not containers?

Thank you all for your help!!!

Best,
S

Yeah,  I made that mistake too when I started.  A lot of these purchased soils are very high in carbon, which means they tie up all your nitrogen, which is a main nutrient to make plants grow. Eventually it will break down to something good for the plants, and when that happens you'll also notice your raised beds will be lower. Decomposition.  I now get clean fill dirt, add half-composted leaves and other yard debris, and fertilize like hell for at least the first year. My one neighbor thinks I'm nuts- haha! Blood meal is a good fertilizer for soil low in nitrogen like yours. I'd also top it off with some clean fill dirt at the end of the season because it will decrease the volatilization of nitrogen from the decomposition of ther wood chip stuff.

One more thing, sometimes these purchased soils hit a point where they suddenly release a lot of nitrogen, but not evenly. What this can cause, in my experience, is an aphid out break.  Give it time and it will mellow out.

Good luck!

Agree with Amit regarding the nitrogen issue.

That stuff looks like it would be a better mulch than a growing medium - too friable with little capacity to hold nutrients and water.

It will take some work to turn it into 'the good stuff' I.e. Bags of cow/chook/sheep manure, mushroom compost, layered with lawn clippings, blood and bone, etc.

Alternatively, and probably the best option, it could be used as a base to create a no dig garden so over time it will improve and be less work/cost. The bark and wood fines, if kept moist, should act like a Hügelkultur bed and grow a lot of beneficial microbial beasties.

50% nitro humus, 20% compost, 20% wood fines, 10% sand

Wood Fine sound like coarse sawdust mixed in with soil = very bad
Sand/gravel is not the same as dirt, they don't have the same amount of bio-available mineral.
Nitro humus sounds very suspicious to me, is that bio-solid, human sewage sludge? https://www.epa.gov/biosolids/use-composting-biosolids-management
Compost is this the usual fire treated compost vs regular bacterial treated compost

NITRO HUMUS http://www.rareearthlandscapematerials.com/nitro-humus.html
 A Dark, rich , fine-textured soil amendment
made of iron and nitrogen stabilized shavings
This premium soil amendment is fine-textured, an excellent
choice for bedding plants, seedlings and container gardens.
INGREDIENTS:

Redwood Shavings

Iron

Nitrogen

If this is 50% of the mix and there's another 20% of 'wood fines' there is a lot of wood in that 'soil'.

hau S Haas, You do not have soil there, you have wood chips. Nurseries do not use soil for sprouting or growing plants, they want to be able to control the amount of water held in the growing medium and they control all nutrients through the water.
For that reason they use mixes that don't hold onto water, it's more like a aquaculture or hydroponic medium that is just used to support the root system of the plant so it won't fall over.

Soil has to, by definition, have mineral content (dirt) and living microorganisms, things most nurseries don't care to have near their plants.

The good news is you have plenty of humic material but now you need the other two parts of the soil puzzle, if you are not where you can dig dirt up to add to that wood chip growing medium, you can buy it bagged.
For every one bag of "nursery mix" you will want two, same sized bags of dirt to mix with it so you are closer to proper mineral content for your plants, just sand isn't going to do the job.

Today many people make this mistake, mostly because it is sold as "potting mix" but it isn't soil or dirt, most of it is badly composted wood chips with fertilizer added to allow things to grow in it.
It does drain well but that is mostly because there is nothing in the mix to hold onto water.
Where I live they even sell "super soil" which is fairly good compost mixed with small wood chips, sand and a touch of clay, and it isn't any better for growing plants than nursery mix.

Hi All!

Thank you for your replies. This is very helpful information, indeed.

Just to be sure I understand, can you let me know what the "dirt" from a garden store might be called when sold in bags?

Also, would it be any help to add pearlite or coco coir to this mix?

Thanks!

Hello again!

One more question: if I want to incorporate the remaining large pile of this "nursery mix" into a lasagna mulching option for my dead-grass-covered yard, would you suggest using it as a top layer like mulch, or a layer further down in the "lasagna" closer to the existing soil (the way you would in a hugelkultur?

Thanks!

Bagged soil will be labeled Top Soil which means it is dirt from the top 6 to 12 inches.

for a lasagna method I would use that as the top dressing layer and perhaps a middle layer if there was going to be enough to do both.

hau S. Haas, no you should not need pearlite or coco coir for a good soil.
Pearlite is used in place of small stones to open up the structure of a soil, coir only adds organic matter and that potting mix has plenty of that so no need for it.
The only thing that might be a good extra addition for a true container soil would be vermiculite (expanded mica) which will soak up extra water and release it back to the soil slowly.
However, if you build good soil, this one addition is also not needed since the organic matter will decompose to humus which will hold plenty of water.
If you live in an arid (desert) region then the vermiculite might be a good addition to a good container soil.

Sorry I missed that question in my previous post.

Redhawk

I've been using just clay soil from my garden mixed with organic matter from the yard and many plants do well in it, especially low-maintenance plants like lettuces and herbs. Didn't cost me a cent. People will tell you not to use regular soil but I have pretty good results with it.

If you have a garden bed to experiment on you can try the free option.