If you are not sure how high to make your raised bed, consider what you want to grow. Some plants are deep rooted, while others only require shallow soil to cover their roots. If you plan to grow different kinds of plants as time goes on, choose a bed height that will work for the deepest rooted plants. For example, if you plan to grow herbs this season, but hope to raise some tomatoes next year, you will want to build (or buy) a bed that is 20” high.
Here’s a guide to the raised bed height needed to grow some popular vegetables, herbs, and flowers:
What grows well in a 6” high raised bed:
Arugula, leeks, lettuce, onions, radishes, spinach, strawberries, basil, chives, cilantro, dill, mint, oregano, parsley, thyme, marigolds and other annual flowers
What grows well in a 12” high raised bed:
Beans, beets, broccoli, Brussels sprouts, cabbage, cantaloupe, carrots, cauliflower, collards, cucumbers, garlic, kale, summer squash, Swiss chard, turnips, lavender, rosemary, sage, borage, calendula, cosmos, lantana, nasturtiums, snapdragons, sweet alyssum (plus everything in the 6” list)
What grows well in a 20” high raised bed:
Artichokes, asparagus, eggplant, okra, parsnips, peppers, sweet potatoes, tomatoes, watermelon, winter squash, pineapple sage (plus everything in the 6” and 12” lists)
When growing vegetables and herbs, consider planting young plants from Bonnie Plants® instead of seeds. These vigorous plants are already well on their way to maturity, so you'll automatically be closer to harvest time!
Caring for Your Raised Bed Garden:
A month after planting, be sure to give your vegetables, herb, and flowers the nutrition they need by feeding them with Miracle-Gro® Raised Bed Plant Food, following label directions. When used in combination with Miracle-Gro® Raised Bed Soil, you see even more bountiful results (vs. unfed plants).
The soil in your raised beds will break down over time; however, you don’t need to replace all of the soil in your raised bed garden to have beautiful, vibrant, or bountiful plants. Before planting the following growing season, add Miracle-Gro® Refresh™ Soil Revitalizer to your old soil, following package directions. It is specially formulated with ingredients to help restore soil structure, renew water retention, and replenish essential nutrients.