Craving homegrown veggies, but not much space, poor growing conditions, contaminated soils, or past failures with container gardening? Consider EarthBoxes®, a growing method developed by Florida farmer Blake Whisenant, working with university researchers and Cooperative Extension. Whisenant, using C. M. Geraldson’s gradient-oriented nutritional paradigm, created EarthBox® as a self-contained system with growing medium, fertilizer, lime, a water reservoir, and plastic mulch cover.
Although Extension Master Gardeners don’t endorse commercial products, EarthBoxes® resulted from research to develop a growing system that manages water and nutrients for optimal plant growth. Having grown vegetables at homes in different states, as well as a local community garden, I know that EarthBoxes® produce better yields in less space than conventional in-ground planting—with minimal maintenance!
How to use EarthBoxes®.
Each box is 29 inches long, 13 ½ inches deep, 11 inches tall, holds 3 gallons of water, and 2 cubic feet of growing medium. Tuck a single EarthBox® onto your deck or create an EarthBox® farming operation! For success, set up your EarthBoxes® with:
- An appropriate growing medium,
- Mixed with the recommended amount of dolomitic lime.
- The recommended type and amount of fertilizer placed in a strip topped with more growing medium,
- Covered with a plastic mulch “cap” that is either black, white, or red.
You need not buy soil mixes, fertilizers, and lime sold with EarthBoxes®—it is often cheaper to purchase these in bulk. Choose either conventional or organic products—just do NOT use garden soil and DO use dolomitic lime rather than other lime formulations. Carefully follow your EarthBox® instructions for the amount and placement of these ingredients—you should NOT add any more fertilizer during the growing season!
For gardening in future years:
- The boxes will last indefinitely—I have one that is almost 20 years old and left outside most of that time!
- The growing medium can be reused for many years—with just some topping up when you replant your boxes the next growing season.
- Replenish fertilizer, lime, and mulch covers every year.
Customize your boxes by:
- Making them mobile on casters to follow the sun;
- Raise them up to waist height;
- Add trellises for vining crops and support for your tomatoes;
- Include frost covers to extend the growing season.
Watering is key!
You must keep the EarthBox® water reservoir partially full, so your plants’ dense root systems are evenly moist. This enclosed system means you cannot rely on rainwater, so boxes without an automatic watering system might require water twice a day by midsummer! The upside is that during wet seasons your boxes will not become waterlogged and/or leach nutrients—one reason Whisenant designed EarthBoxes® was crop loss from flooding in Florida tomato fields!
Adding an automatic watering system makes your boxes almost maintenance-free. The system sold to accompany EarthBoxes® can be a bit difficult to set up (their instructional video provides pointers) and may be vulnerable to coming apart and leaking. To minimize the toll of accidental leaks, I use a timer to limit how long water flows to the boxes; 15 to 20 minutes every 6 hours keeps the reservoirs filled on my eight-box system.
- Use a “Y” connector when you hook up your automatic watering system to allow using your hose bib for other watering chores.
- Make sure you keep any hose bib shut-off valve to the EarthBoxes® open at all times!
- Turn on the faucet far enough to create sufficient water pressure to keep your boxes watered.
What can you grow in your EarthBoxes®?
Just about any vegetable—and many fruits and herbs—grown in our area will grow in an EarthBox®. I do not grow perennials (asparagus, rhubarb, strawberries, and many herbs) in EarthBoxes® because you must disconnect the watering system before frost!
A single box will hold 2 full-size tomato plants, OR 2 eggplants, OR 4 cucumber vines, OR 6 pepper plants, OR 8 lettuces, OR 16 bean plants. This may not seem like much, but I harvested 119 full-sized fruits from the two ‘Better Boy’ tomato plants I grew in my first EarthBox®!
Although EarthBox® provides planting placement instructions for many other crops, I have found it difficult to start seeds in the boxes—use your own or purchased transplants—so I do not grow beets, corn, or radishes in these systems. Trying new crops is part of the gardening adventure, though—experiment to find the best choices for your EarthBox® space!
Not every crop will do well every year but pay attention to timely harvesting and any disease or insect problems and you’ll typically see greater yields than from the same plants grown in the ground—and in a smaller space!
Should you try it?
The downside is the initial investment, so starting with a single EarthBox® or two with a watering system is a cautious approach. There are also many “do-it-yourself” versions of the boxes, and variants on irrigation methods, but I can’t vouch that you’ll get the same results with these substitutes.
If you do try EarthBoxes®, remember that you can consult with those of us who have used them before. Our Extension Master Gardner helpline opens again in March, along with info tables at many gardening events in our area!
Article by Debbie Green, Buncombe County Extension Master GardenerSM Volunteer.
About Blake Whisenant:
What/how to plant: