Ask a Master Gardener

green bean growing on a vine

Growing Beans


I was hoping to grow some beans this year, but have I waited too long to plant? BG

Beans are pretty easy to grow. At our Seed to Supper Farm where we teach Master Gardeners about growing vegetables and then donate to produce to area food banks, we have been planting beans for a while this spring.

We planted our first row of beans in early April. We followed up with another row a few weeks later and just last week planted a third row. This is called succession planting which will spread our harvests out rather than getting all the beans at once. We should be getting pretty close to our first harvest.

We are going for peak production, so we stuck with Blue Lake and Jade. But one of the fun things about beans is that there are so many different types. Other varieties to consider in a bush bean would be Contender and Provider. In a pole bean it’s hard to go wrong with Kentucky Blue, Kentucky Wonder, Meralda, or Pinto.

Bush beans are exactly what they sound like, bean plants that grow like a small bush. Pole beans on the other hand are a vining bean that will need something to climb and support them.

You want your soil temperatures to be in at least the 60s for good germination. Having said that, we planted our first planting when the soil was cooler than this, but it worked out fine.

Since beans grow best in loose soil, it’s a good idea to loosen up the soil a bit, perhaps by tilling. Beans don’t need to be soaked before planting, but you will want to give them a good watering after planting.

OSU recommends planting bush bean seeds about 7 to 9 seeds per/foot row and creating your rows about 18 inches apart. If you plan to grow pole beans, you can plant 2-3 seeds around each support. Last time I grew pole beans, I made tripods out of PVC pipe and let the vines grow up the legs. If you would like something a little more decorative, you can grow pole beans on trellises also. I think it would be kind of fun to have an arched trellis for the beans to grow up and over.

Beans do best in when well fertilized. For example, for a 10’ by 10’ plot of beans, sprinkle 2 - 3 pounds of a fertilizer such as 10-20-10 in that space. If you plan on tilling the soil first, sprinkle the fertilizer before tilling. This way the fertilizer will get worked into the soil. Once the plants begin to flower, you can add about 1/2 cup of that fertilizer for every 10 feet of plant/rows.

Beans don’t like to get dry, so keep them watered. If the soil does happen to get too dry while the beans are blooming, this will cause the blooms to drop, and you won’t be getting the bean harvest you were hoping for.

Also, beans have shallow roots so be careful when weeding. A good layer of mulch will help retain moisture as well as discourage weed development. I haven’t been able to get my vegetable garden mulch down yet and I will pay for that this weekend as I am down on my knees pulling weeds. But as soon as that is completed, the mulch will be going down (he says, hoping that is the case).

You should be able to harvest your bush beans in about 50 to 60 days while pole beans take a little longer. Beans are ready to harvest when they are about the size of a small pencil. They should snap when you bend them. If they don’t you probably waited too long, and your beans will be tough and a little stringy.

As a bushy plant, beans are susceptible to powdery mildew. At the first sign of powdery milder, treat your plants with copper fungicide or neem oil per instructions on the label. When you use horticultural oil, be sure to do a test spray first since heat and oils in combination can damage plants.

Cabbage loopers, aphids, and thrips may come after your beans. Bacillus thuringiensis is a good organic product to treat for cabbage loopers while insecticidal soap works on aphids and thrips. Organics are typically a good choice for a lot of reasons, one of those is that they tend to have a shorter pre-harvest interval than synthetic pesticides.

The pre-harvest interval is the period of time between when you apply the product and when you can safely harvest. Most organics have a short pre-harvest interval while synthetics tend to be longer. For example, some organics have a pre-harvest interval of zero days, meaning you can use them on the same day you harvest. Some synthetics are more restrictive with pre-harvest intervals of up to 28 days. So, be sure to read the label of the product you are using so you can use it safely. And be sure to apply early in the morning or late in the evening to avoid spraying any pollinators.

When harvest time comes, be sure to do so without damaging your plants since you should be able to continue to harvest for a while. See you in the garden!

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at Photo: Oklahoma State University Agricultural Communications Services