Black beans are one of my favorite foods to eat because they taste good and have a high protein content. And it’s easy to grow them in my container garden because they’re not a fussy plant.
You can grow black beans in a container that is at least 12” deep. You can plant several seeds and thin them later to two plants per container. Provide the required sunlight, water, nutrients and harvest the black beans in 100 days.
I’ve written all the steps that you need to grow these black beans in your own container garden. Follow these along and let me know how it goes.
1. Pick a suitable variety for the container
You can get black beans that are of the bush or vine variety. They are also known as determinate or indeterminate types.
The bush variety will grow small but spread wide and the black beans will be ready for harvest at the same time. The vine variety will grow about three feet tall and the beans will keep on growing so you keep harvesting.
If you have a small growing space, I would suggest growing the bush variety. But if you have a larger growing space, you can also grow the vine variety.
The vine variety will require that you use some sort of support like stakes, trellis, or a tomato cage to help encourage the vines to grow vertically.
2. Choose the best time to grow black beans
Black beans are a warm-season plant. It’s best to grow them when the temperature is at least 70 degrees. If it’s too cold, the seeds won’t germinate and the plant growth will be stunted or it may die.
I recommend growing the black beans in late spring as the weather starts to warm up. Make sure to plant the seeds well after the last frost date has passed if you want to ensure the black beans grow.
You want to grow the black beans when the weather will remain at the 70 to 85 degrees temperature for at least three months. This gives the black beans sufficient time to develop and become ready for harvest.
3. Find out how long it will take to grow
The time your black bean seeds will take to grow depends on the variety you are growing. But you can expect the black beans to be ready for harvest about 100-140 days after you have sowed the seeds.
You can use some techniques to help speed up the germination a bit by soaking the seeds in water overnight before planting. You can also use an inoculant in the potting soil that will help encourage the germination and growth of the black beans.
4. Pick the right container to grow black beans
The container you choose will determine whether your black bean plants grow well or not. I suggest using a container that is at least 12 inches deep and 12 inches wide.
This container will help the black beans get plenty of space to develop roots. It will also help you grow several plants in one container that are spaced at a good distance from each other. Growing several black bean plants will help you get a good harvest.
I like to use a plastic container to grow black beans in my container garden. These containers are inexpensive, durable, and lightweight. Plastic containers don’t lose heat or moisture as fast as some other materials like terracotta or metal.
You can choose a container of any material based on your preference but it will change how often you may need to water the plant. You can even reuse a container if you already have one as long as it’s of the required size.
Make sure the container you pick has some drainage holes at the bottom. These will help drain out the excess water in case you overwater the plant.
Black beans don’t like their roots to remain in soggy soil. It can lead to problems like fungal diseases affecting the roots of the black bean plant.
If you pick a plastic container and it does not have drainage holes, you can use a power drill to drill some holes in it.
5. Sterilize the container before planting
You may have bought a new container for planting the black beans or trying to reuse an existing one. But it’s good to ensure the container is free from pests and diseases.
The easiest way to do this is to sterilize the container with a mix of bleach and water. Take 9 parts water and 1 part bleach in another larger container. Soak the container in this solution for at least 1 hour.
You can rinse the container with water to clean the solution from it. Leave the container to dry before you can start preparing it for the black bean seeds.
6. Prepare the container for planting
Now that you have chosen the container for growing black beans, it’s time to prepare it. I recommend adding potting soil to the container and avoiding garden soil.
That’s because the garden soil may contain harmful pests, chemicals, and diseases you may not be aware of. It could contain too much sand or clay. Or it may not have the right pH balance required to grow black beans.
The only situation where you can use garden soil is if you already have an in-ground garden. The garden soil should have been tested and amended with the required materials so it’s fertile and suitable for growing plants.
You want to choose a good potting soil that is sterile and does not contain any nutrients. You can make your own potting soil by mixing 1 part perlite, 1 part vermiculite, and 1 part peat moss or coco coir.
I would suggest adding some organic compost when preparing this potting soil for the container. This compost will improve the texture of the potting soil as well as add nutrients and beneficial microorganisms to it.
You should also mix an inoculant in the potting soil as this will help the black bean roots to fix nitrogen in the soil. This helps the seeds germinate faster and the plants to grow healthy.
Place some newspapers at the bottom of the container so it can cover the drainage holes before you add the potting soil. This helps prevent the potting soil from falling out of the holes.
Now you can start adding the potting soil until it fills up the container. Leave about 2 inches from the top of the container. You will be able to water the potting soil without having to worry about spilling it out of the container.
7. Add support for the vines in the container
If you’re planning to grow black bean vines, you’ll need to support them. This helps them grow vertically which reduces the space to grow them.
There can be several pests and diseases that can attack the vines when they are touching the soil. Growing the vines with support helps prevent this problem.
You have a lot of options when it comes to using support but pick one that is suitable for the space you have. You can choose a simple stake either in the container or in the ground near the container.
You can pick a trellis that you have placed near the container. Or you can use a tomato cage placed on the container growing the black beans.
It’s best to add the support as you’re preparing the container. This helps avoid disturbing the seeds and roots once you have the plant growing.
The support that you choose should be at least 3 feet in height because most black bean vine varieties can grow up to 3 feet tall.
8. Plant the black beans in the container
Black beans have shallow roots that don’t like to be disturbed once they are growing. That’s why I suggest planting the seeds directly in the container. You should not try to start seeds indoors and then transplant them to the container.
You should soak the black bean seeds overnight in water if you want them to germinate faster.
Make a 1-inch hole in the potting soil and plant the black bean seed in it. You can plant 2 seeds in the hole just to ensure that at least one of them will germinate.
Make sure you plant the seeds so that the eye is pointing to the bottom of the container. Cover up the seeds with the potting soil.
Once you’ve planted the seeds, water the potting soil so that it becomes moist to help them germinate. You don’t want to water too much and make the potting soil soggy.
If you have used a container that is at least 12 inches wide, you can plant several black bean seeds in the same container. Just make sure you leave enough space between the seeds.
If you’re planting the vine variety seeds, you can keep them about 4-6 inches apart from each other. If you’re planting the bush variety seeds, they need a little more space to grow. So keep them about 6-8 inches apart from each other.
Keeping a good distance between the seeds will help the plants get the required nutrients and moisture from the soil without competing with each other. It will also keep good air circulation among the plants and prevent fungal diseases due to moist conditions.
9. Provide the required sunlight and moisture
Black beans are a warm-season plant that requires at least 6 hours of direct sunlight every day. Make sure to place the container in a suitable location in your garden.
The black bean seeds will germinate in about 8-14 days depending on whether you soaked the seed before planting and used an inoculant in the potting soil.
It may be that the weather gets too hot during the summer and the plant leaves start to wilt. But don’t worry because once the temperature returns to the expected range, the leaves will return to their shape.
You may also consider moving the container to shade if you find that the afternoon weather is too hot during summer.
Black bean plants require plenty of water to grow well. You want to provide at least 1-2 inches of water every week to the plant.
The easiest way to ensure this is to use the finger test. Stick your finger 1-2 inches in the potting soil to check the moisture. Only if the tip of your finger does not feel moist, should you water the potting soil.
Make sure to water the soil thoroughly so that the entire potting soil and all the roots can get the moisture. You should keep watering the potting soil till the water falls out from the drainage holes at the bottom.
I would also suggest adding organic mulch such as dried leaves, grass clippings, or wood chips to the potting soil. This helps insulate the potting soil from the heat and retain moisture for a longer time.
Just make sure to add this mulch only after the seedlings have germinated and grown to a few inches. So the mulch will not smother the seeds.
Keep the mulch a few inches away from the base of the plant so it does not touch the foliage.
10. Thin the black bean seedlings
Black beans have a good germination rate so you may plant just one seed per planting hole. But I still suggest planting 2 seeds per hole to improve the chances of germination even more.
It may happen that both the seeds germinate and you now have two seedlings growing. This is the time to pull out one of the seedlings and continue growing the other. This process is known as thinning.
It will help one of the seedlings grow into a healthy plant without having other plants competing for nutrients and resources. You can choose to pull out the seedling that does not look healthy. If both seedlings are doing fine, you can just pull one of them out.
You can cut the seedling at the base of the plant with pruners or you can pull the seedling out of the potting soil. You can add the seedling to your compost pile if you have one.
11. Provide fertilizer if required
The unique ability of black bean plants is they can fix nitrogen in the soil. This means the roots of these plants can use the nitrates in the soil and extract nitrogen from them. That’s why it’s said that black bean plants don’t need fertilizer to grow, unlike other plants.
I would suggest adding compost to the potting soil when you’re preparing the container for planting. The compost will provide the required nutrients and beneficial microorganisms in the soil.
The only reason you would add fertilizer to the soil would be if you find the leaves are turning yellow due to lack of nutrients. And I would suggest using a low-nitrogen fertilizer.
Too much nitrogen will encourage the growth of the plant foliage at the cost of the bean pods and you don’t want to do that.
You can use a slow-release granular fertilizer or a liquid fertilizer depending on your choice. You place the slow-release fertilizer granules in the potting soil. With every watering, the granules release nutrients in the soil. Such a granular fertilizer will last in the potting soil for about a month.
The other option is to use a liquid fertilizer that you dilute with water and spray on the potting soil and foliage. This gives an instant boost of nutrients to the black bean plants. How often you may spray such fertilizer depends on how much you have diluted the fertilizer with water.
You need to follow the instructions provided by the manufacturer when using any kind of fertilizer. It will show you how much fertilizer to use based on the plant size. It will also show you how often you need to fertilize the plant
13. Tie the black bean vines to the support
If you’re growing a black bean vine variety, you must have already picked a type of support and added it to your container. Now as the plant is growing, you’ll need to attach them to the support.
Every few inches, you can encircle the vine with support such as the stake or trellis. You can tie the vine to the support using garden twine.
Make a loop with the garden twine as you do this and make sure that it’s not tied too tight as this will damage the vine and even break it off.
14. Harvest and store the black beans
You should check the seed packet on how many days it will take till the black beans are ready for harvest. Usually, they will be ready for harvest in about 100-140 days after planting the seeds.
It’s easy to know when the black bean pods are ready for harvest because they will dry out and turn yellow in color. You can even remove a bean and bite it. If there are no teeth marks in the black bean, it means they have dried out and are ready for harvest.
You can use a pruner to cut the pods from the plant. If there are a few pods, you can remove the beans by opening each pod. But if there are a lot of pods, this will be time-consuming to do.
Instead, you can put all the black bean pods in a pillowcase or sack and hit it against a wall a few times. This will loosen the black beans and cause them to fall out of the pods.
Once you have got the black beans, spread them out on a flat surface in a cool, dry place. Let them dry out for a couple of days before you can store them.
You can store the black beans in an airtight container that you place in a cool, dry place. These beans will last you at least a year without any problems.