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Self-Watering Planters
Yield Bumper Crops

Field Trials Produce Amazing Vegetable Harvests

Cucumbers growing in the Self-Watering Planter
Cucumbers in the Self-Watering Planter.

Fresh, organic produce commands top dollar at supermarkets and restaurants these days. People are willing to pay a premium because they recognize the healthful benefits of eating organic food. They're also discovering that chemical-free food actually tastes better!

So why isn't everyone heading to the garden to grow fresh, healthy, all-organic produce? The truth is that most people just don't have the time, space or experience to grow their own food.

At Gardener's Supply, we began to notice this trend about 10 years ago. So we set out to invent an easy-to-manage, portable little "plot of land" that was less than 2 feet by 3 feet. A water reservoir would end the need for daily attention. An organic soil and fertilizer combination would eliminated guesswork. Voila! Our Self-Watering Planter was born.

Because tomatoes are far and away the most popular backyard vegetable crop in the U.S., we focused most of our attention on fitting out the planter for growing tomatoes. But over the years, as the self-watering planter's popularity has grown, we've heard from many customers who are using them to grow lots of other kinds of vegetables as well. So, during the 2002 growing season, our research and development team set out to see what other kinds of food we could grow in these containers.

Our staff horticulturist, Sarah Niland, began the project in late winter. She ordered all the seeds and planted them under fluorescent lights. In May, she transplanted the seedlings into the Self-Watering Planters, which were lined up (all 25 of them) in our Test Garden. Each planter was filled with a blend of Container Mix and a cup of our All-Purpose Organic Fertilizer. As a control, Sarah planted some of the seedlings into regular garden beds nearby.

During the season, and especially at harvest time, it was clear that the plants growing in the containers were outperforming the ones in the garden. Here's a summary of our results with five of the crops tested last summer:


We had great results with a seed variety called Master Chef Blend. This blend contained four loose-leaf varieties, a butterhead and a romaine. "The lettuce tasted great, of course," said Sarah, "but it also looked really beautiful in the planters." We had better results with this cut-and-come-again mix than we did with a planting of six head lettuces. The cutting mix could be re-harvested several times over a two-month period.

Variety grown: 'Master Chef Blend'
Spacing in planter: 3 rows of 4 plants.


Onions growing in the Self-Watering Planter
Onions growing in the Self-Watering Planter.

We planted onion plants, rather than sets, having purchased the thin, scallion-like plants through the mail from a grower in Georgia. The results were very impressive. The onions grown in the self-watering planters measured more than 4 inches in diameter when they were harvested, while the largest onion from the in-ground bed was just 2 inches in diameter. You can also grow your own onions from seed. For details, read the blog post Growing Onions from Seeds, Sets and Transplants.

Variety grown: 'Walla Walla Sweet'
Spacing in planter: 2 rows of 6 plants


For testing, Sarah chose a variety called 'Amira', which is ready for harvest in about 54 days, and is best picked when 4 to 5 inches long. It is reputed to be disease resistant, but we spent quite a bit of time squishing cucumber beetles and squash bugs and lost several of the plants. One of the planters produced 35 pounds of cucumbers.

Variety grown: 'Amira'
Spacing in planter: 4 plants with a bamboo support pole for each plant

Pole Beans

In the bean-counting category, we produced an average of more than 6 lbs (395 beans) per planter. We made a bamboo teepee for each of the planters, tying the canes together at the top. We had several severe windstorms last summer and strongly recommend that if you're growing beans, you should put your Self-Watering Planter in a protected location or tie the support poles to a rigid structure nearby.

Variety grown: 'Kwintus'
Spacing in planter: 4 beans at the base of 4 bamboo poles

Bell Peppers

We put four pepper plants in each self-watering planter, and harvested an average of 45 peppers (9.25 lbs) per planter.

Prior testing had shown us that we could produce 30 lbs of tomatoes from one of our Self-Watering Planters. But we were pleased to learn that they work just as well for many other vegetable crops. Now we know why so many people are buying two, three or even twelve of these planters at a time!

We have also learned that more than half of the people who use these self-watering planters also tend regular gardens. In many cases they are using the planters to deal with a special challenge such as deer, poor soil or lack of sun. But there are lots of other folks who simply couldn't or wouldn't be gardening if they didn't use these planters. For kids, they provide a manageable amount of space they can call their own. For people with limited mobility, they bring the garden within easy reach. For city dwellers, they can turn a balcony or fire escape into a salad bar.

If you give this 21st century gardening method a try this summer, here are some additional tips to help ensure your success:

Pick the Right Location. Vegetables, herbs, and fruit require at least six hours of direct sunlight each day. If your backyard is too shady, consider locating your planter on a deck, balcony, front step or even in the driveway.

Don't Skimp on Soil. Good soil is important in the garden, but it's especially important in container gardens. Avoid using garden soil, which is heavy and will compact after repeated watering. Our Self-Watering Container Mix is the ideal medium for these planters. If you want to grow organic, choose the Organic Self-Watering Container Mix. It's lightweight and has a coarse texture that retains water, yet ensures good drainage. What else to add? Make sure to mix in a generous cupful of all-purpose, organic fertilizer before you plant. Some crops will still require bi-weekly feeding during the season, but the slow-release fertilizer will maintain good overall fertility. If you have a bucketful of compost available, we also recommend mixing that in before planting. Compost contains billions of beneficial microbes and lots of trace nutrients that promote health and vigor.

Don't Forget to Water. If you want a bumper crop, watering is crucial. To make it easy, invest in an irrigation system. If you don't use an irrigation system, check the moisture level of the soil every few days. During the hottest part of the summer you may need to fill the water reservoir every other day. Repeated cycles of wet and dry will damage the plant's root system and it won't produce a bumper crop. Every two weeks, use a little water-soluble, organic fertilizer.

Kathy LaLiberte, the Innovative Gardener

Kathy LaLiberte has worked for Gardener's Supply since it began more than 25 years ago. She lives and gardens in Richmond, Vt. Click here to read more of her Innovative Gardener essays.

Last updated: 7/9/19