Best Soil For Raised Bed Vegetable Garden

[Karl Helser]

Just put in a 8' x 4' raised garden bed. I'll need about 2 cubic yards of soil. We'll be planting such things as peas, spinach, tomatoes, lettuce...etc.
What would be a good soil mixture. We plan to buy bags, but are unsure of the ratio of the mixture.

[CharlieBear]

Here is some of what you are up against---
Potting soil is not soil but a soilless mixture usually containing wood product remains, perlite or equivalent, possibly sand, fertilizer etc. It is best used for large pots that have to be moved in and out during the year.
"top soil" in most states can be anything and generally isn't very good stuff. It often is full of weed seeds and can be subsoil in most states. In a few states it is little more than soilless mix. Even if you go to a yard and buy 1 or 2 yards at a time it can be little more than clay or can even be mildly contaminated.
One solution that works is to go to one of those places like a fuel company that sells bark mulch and buy mushroom compost. It will sink down and you will have to add compost etc year after year to bring the level up and the nutrients back or even a little composted cow manure. The one draw back to mushroom compost is that it has a slight salt component.
So, if you are concerned about that you could mix 1/2 mushroom compost with "top soil" or even potting soil.
If you buy anything in bags the cost will eat you up alive quickly. I just noticed where you are from. Go to Mt Scott Fuel and get mushroom compost. One cubic yard will fill a standard size pickup truck bed, so if you don't have access to one I would ask around to see who has one they will let you use or drive it there and back for you. Note in the portland metro you will likely get clay and very weedy clay if you buy top soil, as many of my gardening friends have found out. If you want to ask more questions send me a personal I usually forget to check back on questions I have answered. There are other possiblilities of course, but space is limited.

[rainbowgardener]

Two cubic yards sound excessive for one bed, even if it is deep. I have beds that are 18" deep, 8' x 4' and if I remember right, it took one cubic yard to fill it. But if you are dealing in cubic yard quantities, it is way cheaper to get it trucked in. Get someone to deliver you a cubic yard of topsoil and then fil in the rest with bags of potting soil, compost, composted manure.

[cynthia_h]

Hypothetical math calculations:

8' x 4' x 1' deep = 32 cubic feet = 1 cubic yard + 5 cubic feet left over

8' x 4' x 18" deep = 48 cubic feet = 1 cubic yard + 21 cubic feet left over

8' x 4' x 20" deep = 53.3 cubic feet = 2 cubic yards, almost exactly (2 CY = 54 cubic feet)

8' x 4' x 2' deep = 64 cubic feet = 2 cubic yards + 10 cubic feet

So it looks like these may be 20" deep, or the OP simply wants to make his life easier by rounding off to the nearest cubic yard.

Cynthia H.
Sunset Zone 17, USDA Zone 9

[Karl Helser]

Thanks Cynthia, you are correct. My bed is 20" deep....I already did the math, and that's how I came up with two yards.

FYI... 1 cubic yard = 27 cubic feet
1 cubic foot = 1728 cubic inches
With those factors and the dimensions of the bed, it's real easy to calculate how many cubic yards needed.

Thanks rainbowgardener and CharlieBear, you were very helpful with your information. I am definitly going to use a large pick-up truck instead of bags.
I found a landscape supplier that has what he calls his Blended Premium Soil. It's a mixture of sandy loam, mushroom compost, and premium compost. Sounds like just what the vegis ordered

[cynthia_h]

Be sure that the Premium Soil is designed for "containers." It may be designed for in-ground use.

Raised beds are a kind of large container, and need larger pore spaces in the soil than the native ground does. This is why many potting mixes (and even Mel Bartholomew's recommended soil blend for Square Foot Gardening) include perlite, vermiculite, or other "air-friendly" (?) ingredients.

Cynthia

[DiJon]

I've talked to many raised bed gardeners in Portland. the native soil is so clay filled, and it rains so much here, that you really don't want too much of it in you beds, or you will be battling damping off all spring. You can get a potting soil mix called 5f and mix that with some manure compost, worm castings and a cup or two of feather meal and bone meal add the compost, feather and bone meal every year.

[Gary350]

I buy Peat Moss in the 3.8 cu ft bales at Lowe's when it is on sale. I dump in on top of the soil 6" deep then I till it into the soil. Then I put it in the raised beds it is 50/50 peat moss and soil. It works great and does not cost much.

[floridahillnursery]

Hello, Mushroom compost and peat moss blend. If there is a mushroom factory in your area they unload the compost by the tonn and its very cheap.

[LA47]

We are putting in raised veggie beds next year. Getting decent topsoil is out of the question in our area. I planned mixing one third compost and well aged manure with the soil. I'm very nervous about using peatmoss as it seems to repel water yet that is what SFG recommends as 1/3 of the mix. What keeps the peatmoss from repelling the water in the raised bed?

[applestar]

I think if you add 1/3 compost, you wouldn't need peat moss.

I never buy peat moss any more. Most bagged potting soil are still made with them, so I end up with them in the compost pile and raised bed eventually, but I usually only use turned over sod (from other areas -- I only fork the ground where raised bed is to go), good soil from other areas of my poperty (usualy under the leafpile or stickpile), compost, fall leaves, grass clippings and cut weeds, sand, composted mulch, cardboard for weed suppression, small sticks and branches.

Not in that order but layered as sheet mulch/compost. Dolomitic lime, rock phosphate, and greensand. Sometimes used coffee grounds and soaked alfalfa pellets.

[Gary350]

In my TN garden I used peat moss only. I would buy several of the 3.8 cu ft bails every year and till them in to the garden soil. The Pepper Plants especially loved it for some reason pepper plants would get 6 tall, bell peppers were 5" diameter, sweet banana peppers were the size of real bananas. Tomatoes, squash and beans liked it too. Corn and okra did not seem to care.

I would dump peat moss 4" deep 20" wide the width of the tiller in the row I want it, then till it in. It was like a raised bed without building a raised bed with boards. It only took 10 minutes to dump peat and till. About 50% of the peat had to be replaced ever year it composts away pretty quick. One bale of peat moss per row would tripple my pepper harvest. All the greens loved it too.

I made 3 lbs of red chili powder one year ground up dried chilis in the kitchen blender.

I could never make enough compost to do what I needed, peat moss was the cheapest alternative.

[imafan26]

Peat moss I think has a pH around 5.5. It provides good root support and peppers and most plants like a slightly acidic soil. It does not provide much in the way of nutrients so I suspect you also fed them very well.

Peat moss is a natural product but it is being mined faster than it is being made. I'd use more of it in my garden, but I can't afford it. So, instead I use compost and I will dump out the peat lite from my potted plants into the garden as well so it does get a little bit of peat moss.

[jon052101]

hi, if i mix .75 cu ft of composted manure and .75 cu ft of topsoil, is it the same as 50/50? thanks

[ElizabethB]

My 2 cents

Option 1 - purchase bulk soil
advantage - less expensive
disadvantage - weeds and soil quality - have to do a soil test

Option 2 - bagged soil
Advantage - easy to handle
disadvantage - expensive

Option 3 - 1/3 compost, 1/3 course horticultural vemiculite, 1/3 peat moss.
Advantage - virtually weed free except for weed seeds that birds drop, no more expensive than bulk soil if you shop around for your products and have your own compost
disadvantage - you have to mix it

SOOO lots of options.

Good luck