I was smitten with my driveway last summer. For several weeks, it produced tasty tomatoes, peppers, eggplants, summer squash, basil, bush green beans, and cucumbers. Throw in some lettuce, Swiss chard, and beets, and I ended up with much more than a garden; it’s also a conversation piece, a local gathering place for neighbors passing by, a teaching center for children, and a chance to spread the joy of gardening.
But wait! The driveway surface is concrete. What’s the secret of succeeding with an annual garden bounty — a ton of fresh produce — in such a location? Why turn an automobile parking place (or basket-ball court, as the case may be) into a garden? Well, necessity is the mother of invention. You could also use a deck or a patio, or any place in your yard that gets good sun exposure.
Location and Creativity
When we moved from Pennsylvania to Raleigh, North Carolina, 26 years ago, one of the first jobs on my to-do list was to remove a 30-by-50-foot patch of sod on the side of the house for our new garden plot. The sun shone well on the spot we chose, and for 15 years we had a traditional dirt garden. Then, because of the ever-growing trees in the yard, our garden spot began getting less and less sun, and production began to drop off. An area that gets at least six hours of direct sun will work for a garden plot, but when that hourly exposure drops to four hours or less, it can devastate a harvest.
Not having a productive garden was too depressing to consider. Scanning our property for a place where the sun shone adequately revealed that our driveway was the prime location. Clearly, removing concrete wasn’t practical, but using the space by growing our garden in containers was just the ticket. Then, a few years ago, we added straw bales to the mix.
Anything and everything that can be grown in a traditional dirt or raised-bed garden can succeed when using containers or straw bales. The key to success is in understanding the needs of the particular crop type: its optimum root zone (dimension-wise), watering and feeding needs, and means of support (if it’s a vertical or vining crop). Figuring all that out took a few years of experimentation along with a bit of logic and research. We’re so pleased with the results that it’s hard to imagine going back to the typical dirt garden plot.
Planting Options and Growing Techniques
Traditional dirt gardens, raised beds, containers, straw bales, hydroponics, greenhouses, and vertical gardening arrays are some of the many options to adapt your gardening plans to the infinite possibilities of yards, conditions, and growing zones. Any of these options will work well given some trial, experimentation, and patience. Most gardeners are familiar with an in-the-ground dirt garden, and many install raised beds. Adding containers and straw bales to your gardening tool belt will increase your options, and allow you to grow something great wherever the sun shines best in your yard. Just make sure you jump into new growing techniques gradually, as each has its own set of considerations to learn for maximum enjoyment and success.
See “Comparison and Success Factors” photo to view the differences between traditional dirt, straw bale, and container gardening.
Using Straw Bales
While often thought of as a recent technique, straw bale gardening originated in the 1950s, when the pickling industry needed a new way to grow cucumbers. Related in a way to the lasagna gardening principles of Ruth Stout, the technique was described by Gary Wade at the University of Florida in the late 1970s, and a few years later in a 1982 Mother Earth News article by C. Don Knight. Subsequent articles and books, combined with social networking, are expanding the awareness and popularity of the technique.
I’ve come to cherish gardening with straw bales since I first dabbled with the technique in 2014. I think of a straw bale as a 40-gallon-capacity planting zone, which creates great potential for healthy plants and heavy yields of produce. If you’re new to this type of planting, I recommend you use just a few bales the first season to see if this technique is for you.
Difference between straw and hay bales. Think of a drinking straw — hollow and rigid. Straw bales are tightly packed bundles of just such “straws” of dried hollow stems. Hay bales, on the other hand, are made up of bundled grasses. The most commonly used and widely available types of straw bales are composed of wheat. Options such as oat, alfalfa, and barley bales work fine. Big-box hardware stores often stock straw bales, as do many smaller local gardening centers. It’s important to ensure absence of persistent herbicides in the bales. I was bitten by this a few years ago, when three of my bales killed my tomato plants. Be sure to ask your source about this, or your efforts could be wasted.
Plants to grow. There’s really nothing I wouldn’t try in a straw bale. It comes down to your hours of sun, your available area (the space between and around your bales), and your ability to regularly maintain the bales (particularly with regular watering and feeding, and providing support of some sort for taller or vining crops). Some very hungry, very tall veggies, such as corn, aren't recommended to grow on a large scale because of their propensity to topple, but it may be fun to try one bale just to see how it goes — it’s something I’ve yet to do myself.
For each straw bale, use only two tomato plants, two eggplants, or two pepper plants. For all other crops, use spacing as if you were planting a typical dirt garden to guide you in determining the number of plants or seeds needed.
Preparation, materials, and timing. Purchase and position your straw bales at least two weeks before you wish to plant in them. (You can prepare them many weeks in advance of planting, but two weeks is the minimum.) Position the straw bales as you would containers or a traditional dirt garden, and remember, the more sun, the better.
Bale preparation is a process where adding nitrogen begins the breakdown of the stiff, dry straw, en route to an ideal environment for plant roots. The three necessary materials for bale preparation are a nitrogen source, a balanced fertilizer, and plenty of water. Non-organic nitrogen sources with nutrition numbers such as 29-0-5 (relative percentage of nitrogen, phosphorous, and potassium, typically abbreviated as N-P-K), work great. Organic sources, such as blood meal, have less nitrogen per volume, so a greater quantity is needed to achieve the same result. For the balanced food, a typical 10-10-10 will work fine, and many organic alternatives have numbers more in the 5-5-5 range, meaning you’ll just need to add more if using them.
The treatment is simple. Heavy doses of the high-nitrogen material (1/2 cup per bale of the 29-0-5 treatment, 1 cup of blood meal, and similar organic N sources) are sprinkled over each bale, then water is applied until the bale is saturated (typically 30 seconds of watering per bale — it should run out the bottom). This heavy treatment is carried out three times, on alternating days (Days 1, 3, and 5), with heavy watering on days in between (Days 2, 4, and 6). Days 7, 8, and 9 are for half-applications of nitrogen, then deep watering. Day 10 is for a heavy application of the balanced food — 1 cup of 10-10-10, and double that amount for materials of half-strength — followed by deep watering. Water deeply for the next four days. Day 14 is the first possible planting day.
Mushrooms and grass. Soon after completing the straw bale preparation, mushrooms typically start to emerge. They’re harmless to the plants, but let the bales go through this mushroom-sprouting phase before direct-seeding, as the young seedlings can get pushed out of place. Grass may also start to grow out of the bales; it’s completely harmless.
Seedlings or seeds? Seedlings are recommended for crops that take a long time from seed, such as tomatoes, eggplants, and peppers. Other items, such as lettuce, beets, radishes, carrots, chard, squash, cucumbers, and melons, as well as various herbs and flowers, can be direct-sown or planted as seedlings.
Planting seedlings in straw bales is as easy as using your hands or a trowel to create a “divot,” popping the seedling out of its container, and positioning it as deeply as you can, just as if you were planting in soil. Fill in the gaps with good-quality planting mix, bringing it level with the top of the bale. Mulch around the plant with untreated grass clippings, shredded leaves, or shredded bark, and then water the plant deeply at the base.
Start planting seeds by applying a 2- to 3-inch layer of good-quality planting mix to the top of the bale and patting it gently in place. Plant the seeds at the recommended spacing and depth, and then gently water. For small-seeded crops, such as radishes and carrots, which have shallow roots early on, monitor the moisture level of the top planting mix carefully. It may be necessary to loosely cover young seedlings with newspaper or floating row covers to preserve moisture until the plants grow large enough to no longer be at risk of dying of thirst on hot, sunny days.
Strings up or down? Straw bales perform equally well whether they're used with the strings placed up or down. Strings on the side mean slightly taller bales, and strings on the top mean more stable bales because of more surface area with ground contact. The biggest mistake is cutting the string. A bale is tied very tightly, and a broken string will produce a pile of straw that’s no longer suitable for planting into.
Watering and feeding. On hot summer days, when the sun shines extensively, straw bales will dry out quickly, as will the thirsty roots of the mature plants planted in them. Research your chosen plants for watering guidelines, and pay close attention to wilting plants on hot summer afternoons — a sure indication they’re thirsty. I find myself watering my straw bales daily.
One tip for providing consistent water to straw bales, and reducing labor, is to run a soaker hose down the center and cover it with planting mix. This is particularly beneficial for direct small-seed crops, such as carrots and radishes, and will reduce die-off from small seedlings becoming too dry when their roots are still small.
Feeding is recommended on a weekly schedule, as the vigorously growing plants and frequent watering will lead to nutrient depletion. Use a plant food of your choice, and follow the directions on the label.
Supporting plants. There’s room for creativity when providing support for vining or tall-growing plants. Placing stakes into the bales themselves works only briefly, because the bales will soften as the season progresses, and heavy plants will pull the stakes over. I’ve found that placing large containers of soil behind the bales provides a place to insert support stakes for tying up tall crops. I’ve also used tomato cages to support vining vegetables, such as cucumbers, with great success. I insert the cages into the bale and anchor them using stakes embedded into pots of soil placed behind the bales.
Pest problems. I’ve heard of mice, rats, snakes, and ants taking up residence in straw bales, but I’ve never personally experienced any critter or pest issues. However, as with any gardening technique, you should be vigilant, so such issues can be dealt with as soon as they arise.
End-of-season disposal. Depending on the crops grown, as well as the seasonal conditions, the straw bales will be partially or completely collapsed by the end of the season. The straw will convert to dark, perfectly textured compost or loam. As long as the plants in the bales were healthy, the materials that remain can be used as compost or mulch going forward.
If it holds planting mix, it’ll grow plants successfully. Notice I said “planting mix,” not “soil” and not “dirt.” The foundation for success with containers is the nature of what you put in the pot, and how you care for your plantings. Filling containers with garden soil that contains disease spores is a surefire way to bring unnecessary risk into your garden.
Choosing containers. The two most important decisions when choosing containers are ensuring that they have drain holes (unless you’ll use specially designed self-watering containers) and that each container is the correct size for the crop you plan to plant in it. Terra cotta pots look nice and work fine, but they need more watering because of their porous nature. Self-watering containers, though more costly, reduce the need for watering and provide a safeguard when you’re away from your garden and can’t water regularly.
The vegetable types that are most sensitive to proper sizing, with respect to container capacity, are tomatoes, peppers, and eggplants, all of which have significant root systems and a high demand for water and nutrition in the heat of summer, and vining crops, such as squash, cucumbers, and melons, which are heavy feeders. Tall (indeterminate) tomato varieties need a container with a minimum capacity of 10 gallons, while determinate and dwarf tomatoes, along with peppers and eggplants, need 5-gallon containers. Most other vegetables, flowers, and herbs can be planted using the recommended spacing, fitting in as many as possible in whatever size container you choose.
Filling the containers. “Garbage in, garbage out” is a familiar saying that applies to gardening. If you use poor soil mixes with too much or too little drainage, or that are infused with various diseases, you’ll be inviting problems. My preference is to use products called “soil-less planting mixes” rather than “garden soil” or “top soil.” Bump up the water absorption ability by blending it with compost or composted manure. Aim for a sterile, free-draining mixture that has some water retention.
Watering and feeding. Weekly watering may be sufficient when the plants in your containers are small — recently germinated through a few weeks’ growth, which typically corresponds with cooler spring days. The plants will tell you when they’re thirsty by wilting a bit during the hottest part of the day. Mature plants are very thirsty and may require daily watering. Using a soaker hose, or, even better, a drip irrigation system with individual transmitters for each container, will reduce the effort you expend watering.
Frequent watering leads to a parallel loss of nutrients through the bottom drainage holes. Once container plants become established, after a month or so, plan to feed them weekly using your favorite plant food at the suggested dose.
Plant support. The main issue with supporting tall-growing plants in containers is stability. Inserting a stake into the container will only work until the fruits grow large and become heavy, and then the container will inevitably tip over. A better solution is to place an additional container filled with soil adjacent to or behind the container with the plant. If the supporting stake is inserted into the pot that contains only soil, it will separate the stake from the weight of the plant and keeps things upright much longer.
If the containers are on a surface adjacent to dirt or lawn, you’re in luck. Drive the stake into the soil and position the containers at the edge so that plants can be tied to the adjacent stake. Tomato cages and similar types of supports can be inserted over the plants into the containers, but they, too, will likely become unstable and topple over as the season progresses; position a pot filled with soil next to the caged plant and tie the cage to the stake in the plant-free container.
Critters and disease. Beyond using high-quality potting mix and ensuring that the plants are supplied with sufficient water and regular feeding, the main issues with containers will be those shared with traditional dirt-plot gardeners — critters and diseases.
Though some diseases are far less common with container-grown plants, many are airborne and will similarly bother your plantings. The additional vertical space between dirt-grown and container-grown plants may offer some protection from smaller critters, such as slugs and rabbits. However, curious and inventive pests always seem to find a way, so tactics similar to those used with standard gardening may need to be applied.
Reuse of planting mix in subsequent years. As we garden and learn more, we often find our minds changed and our techniques altered. This is the case with my philosophy on reusing container planting mix. I used to recommend tossing the used planting mix and starting fresh each season, borne of my focus on a very disease-susceptible crop — tomatoes. More recently, though, I’ve decided that if the worst that happens is the inevitable lower and rear foliage spotting that's due to the fungal diseases Septoria and early blight, then the planting mix in the pot is fine for reuse. This philosophy can be used for all crops. If the plants do well, you can reuse the planting mix. But if they suffer from a disease that had its origins in the root zone, toss the planting mix and start fresh.