Build a Raised Bed Garden: Quick, Easy, Cheap
Build a 4' x 4' Concrete Block Raised Bed
Use concrete blocks to build a raised bed and fill it with good garden soil. It's quick, easy, and lasts forever.
A 4' x 4' raised bed is big enough to grow all the produce to make fresh spaghetti sauce and freeze or can a few jars for winter.
The blocks are 7" wide and 9" long, so the bed will not be 4' x 4'. The block bed is 55" long. That works out to about 4 1/2'. That sounds OK, but the interior garden space is 3 1/3' or, about 40" wide on the inside. We built this to replace a wooden frame raised bed, and the concrete block bed has slightly less space.
Start filling the bed with layers of newsprint. The paper smothers any weed or grass seed. We also added the rotting boards from the raised bed that was replaced.
Filling the Raised Bed
- First, cover the ground to kill any grass and discourage weed seeds. This newspaper or newsprint layer can also be recycled office paper or cardboard. The important thing is to overlay the paper or cardboard. Make sure the materials overlap. If using paper, make sure to have several layers. Use what you have; even a thick layer of shredded paper will work. Water down the paper.
- Next, layer brown and green materials as you would when making a compost pile. Add more "brown" carbon-rich materials than green. To use "green" nitrogen-rich materials, apply thin layers of wet food and cover with dry materials.
If all this crazy layering is like making lasagne and taking too much of your precious time, mix everything together in your wheelbarrow and dump it in the raised bed. Use the coarsest materials on bottom. Top with your premium soil to get plants off to a good start.
Green and Brown Compost Explained
"Brown" carbon-rich materials are shredded leaves, wood ash, straw, sawdust, shredded newspaper and wood chips.
"Green" nitrogen materials are fresh or green materials, such as kitchen scraps, coffee grounds, melon rinds, and corn cobs. Add apple cores, eggshells, vegetable peels, and that scary green thing in the back of the crisper drawer.
Grass clippings contain as much nitrogen as manure. A bed is best built a year ahead of using it. Start in the late summer and fall, when there is an abundance of vegetable scraps, grass, and leaves.
Keep a covered container for food discards in the kitchen during canning and preserving season. Ask coffee shops for grounds. Use the discards when cleaning your hair brush, dryer lint, paper towels, cardboard egg cartons, and nut shells.
Build It, Fill It, Plant It
If you are building a bed for immediate use, start the same way, with thick layers of paper, cardboard, and shredded office paper, and then water. I am replacing a bed that had good garden soil. That soil will go back into the new concrete block bed. I have compost and shredded leaves to mix in as well.
Starting from ground zero, use about 40% peat or core. Core has a few more nutrients, holds more water, and is less acid. Add moistened Canadian sphagnum peat moss or core into the raised bed. Stir in a combination of bagged topsoil, animal manure, sand, perlite, and vermiculite.
If you do use some garden soil, sterilize it first. This will keep you from transferring soil borne weed seed, insects, and disease into your new raised bed garden. Bake soil at 200° F on cookie sheets for 20 minutes, stirring once about halfway through.
Top the bed with your best enriched gardening soil for planting.
Enrich your "new soil" with a slow release fertilizer. Or, incorporate (N) "Nitrogen", (P) "Phosphorus" or (K) "Potassium", by adding (N) blood meal, (P) bone meal, and (K) greensand.
Bagged and Soiless Garden Soil, Bad Paperback Books
Materials that would normally be used to make potting mix can also be added to a raised bed. Additions to the soil include peat moss, vermiculite, sand, perlite, core, or compost.
Soil supplements are used to hold moisture, making the water available to the plants. These materials can lighten and aerate soil. Clay soil can benefit most from materials that hold moisture and lighten the growing medium.
Coir (coconut husks) is being marketed as a replacement for peat and as a soil amendment. It will also lighten up garden soil in raised beds or containers. Like peat, it holds moisture in the soil and improves drainage.
Coir is a renewable resource. Peat comes out of bogs that took millions of years to create and is rapidly being depleted. Technically, peat is a renewable resource, but few of us have a million years to wait.
Bury food scraps, shredded paper, dust bunnies, and dryer lint while building the block bed. Be creative. Suitable organic matter includes those sad limp green things in the crisper and old, holey cotton socks.
5" Square Containers
Nasturtium, "Cup of Sun" tumbles over the edge of the raised bed in the photo above. Flowers in the garden attract pollinators and cover soil to prevent weeds.
I think the border of 5" squares in the concrete blocks are a bonus. Will the little 5" squares be hotter or cooler than the raised bed? I will experiment with a raised bed bordered with herbs.
I'll try the small "Spicy Globe" basil plants and little clumps of chives, parsley, chervil, cilantro, cutting celery, or the small "Signet Starfire" marigold.
Little Plants for 5" x 5" Spaces
The best reason I can think of for building a raised bed garden: you will never have to till again.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.