Choosing Raised Garden Beds

Photo of wood and metal raised garden beds.

After much experimentation over the years, I’ve decided that raised garden beds are my preferred way of growing vegetables. Why?

  • They reduce weeding by about 80%. There is no “edge” for grass to infiltrate, and when planted intensively (like “square foot gardening”), the garden plants shade out most weeds by July 4th.
  • They eliminate the need for rototilling.
  • It’s easy to fill them with good soil, and maintain its fertility.
  • Open-bottom beds let plants’ roots “forage” below the ground level for nutrients and water.
  • They add to the beauty of the garden! Any set of similar beds will make a very tidy-looking garden. The beds themselves can be decorative though your selection of materials, shapes, sizes, and accessories.
Photo of wood and metal raised garden beds.
4×4′ wood raised beds and 4′ diameter steel fire pit rings combine to make an attractive front-yard garden. 2′ tall fences keep out rabbits and woodchucks. Wood chip mulch eliminates mowing and weeding around the beds.

If you are thinking about building or buying raised beds, here are some things to think about:

  • Standard bed sizes are rectangles 4’x8′, 2’x8′, 4’x4′, and to a lesser degree, 3’x6′. If you choose among these sizes, you’ll also have a larger range of fences, trellises, screen covers, cold frames, etc. to choose from to use with your beds.
  • If it’s your first time gardening,  I recommend no more than 64 square feet of garden beds (e.g., two 4’x8′ beds). That’s enough to feel like a “real” garden, but unlikely to overwhelm you in your first year.
  • Round beds look delightful, but are a pain to fence and mow around. You also lose 3.5 square feet of growing area compared to a square bed of similar width.
  • Most people can easily reach across 1.5-2′ (18-24″). If your bed is up against a fence or wall, don’t make it more than two feet wide. Up to four feet wide is fine if you can work the bed from both sides.
  • Plain untreated pine 2″x8″ boards are great. They will easily last 8+ years (in Michigan…probably not in the deep South due to termites), and they are thick enough not to warp and bend. Cedar is overkill.
  • Use 1/4″ x 3″ lag screws to hold the 2″x8″ planks together. Regular deck screws aren’t sturdy enough.
  • The cheapest, easiest, best-quality approach is to order “garden blend soil” (top soil + compost) from a local nursery, who will deliver it by dump truck. Fill beds to the top; the soil will sink a couple inches. Plan around 1/2 cubic yard of dirt per 4’x8’x8″ bed. When in doubt, order a bit MORE dirt.
  • Also acceptable is 4-6″ of horse manure topped with 4+” of dirt. Heap the bed; the manure will settle by half within a few weeks. Squash will LOVE this; tomatoes will likely develop blossom end rot the first year. After the worms have had a year to work the soil together, an you have sowed, planted, and pulled out a season’s plants, this will be absolutely amazing soil for anything you want to grow.
  • If you set an 8″ tall bed frame directly on sod, and fill it with at least 6″ of dirt and manure, it will kill the grass underneath. No need to first dig out the sod, lay down cardboard, etc.
  • For wood chip paths, lay 3-4″ of wood chips on corrugated cardboard between beds.  Be sure the cardboard overlaps at least 6″ on all edges. This will kill most grass and weeds, except those with extensive root systems.

See my other posts on Starting a garden from scratch and What should I plant in my first garden?

Published by Emily

I'm an instructional designer and gardener based in Ann Arbor, Michigan. Free moments find me in my garden or the forest, hugging trees and all that jazz.

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