Growing Runner Beans in Containers: How Deep are Runner Bean Roots?

Affiliate Disclaimer: As an Amazon Associate I earn from qualifying purchases.

If you are limited on space, climbing runner bean varieties such as “Enorma” or “Polest ar” are great to grow as they are very high yielding and produce a lot of beans relative to the area that they take up.

So if you only have a very small garden, or maybe just a balcony, and are looking to grow runner beans in containers, how do you create the best growing environment to ensure a strong and healthy crop? Here we will take a look at the ideal conditions that runner beans need in order to survive and thrive!

The roots of runner beans typically reach depths of around 20 – 30cm, and containers used to grow them should have a depth of at least 45cm. This is because, as well as accommodating the root system, containers need to be large enough to retain adequate moisture and sustain the plant throughout the day.

Lets go into some more detail and look at the pros and cons of growing runner beans in containers:

What are the Advantages of Growing Runner Beans in Containers?

There are several reasons why you may choose growing in containers over growing directly in the ground for your runner beans:

– Containers are ideal for small spaces – Only having a small yard or balcony is no barrier to growing your own veg!

– Containers improve accessibility – Containers can be placed at virtually any height and location to allow for easy access.

– Containers give you complete control over soil type – They will also tend to be more free draining than in-ground beds.

– Containers help with pest control – You are likely to have less problems with snails and slugs, especially if you place copper tape around the container edge as a deterrent.

What are the Disadvantages of Growing Runner Beans in Containers?

But of course there are a few drawbacks to container gardening to be aware of too:

– Containers can dry out quickly – Because they are free draining, containers dry out quickly. So frequent watering will be required.

– Nutrient levels can be lower – Growing in containers can mean lower nutrient levels – something which is not helped by the frequent watering required – so extra feeding is often needed.

– Soil temperatures will fluctuate more – Fluctuations in soil temperatures will be more extreme in containers than in the ground. In spring, the soil in containers will warm up quicker than the soil in in – ground beds.

How Deep are Runner Bean Roots?

Runner beans have long, tuberous roots, with nodules of nitrogen attached.

Roots on climbing beans typically extend up to a depth of around 20 to 30cm.

What Size Container do I Need for Growing Runner Beans?

As runner beans have long roots, a minimum container depth of 45cm is recommended.

That said, the job of a container is not just to accommodate the root system of the plant: it is also about moisture retention. Runner beans need lots of water and containers need to be able to store at least day’s supply.

As a rough guide, runner beans ideally need a container with a length and width of at least 45cm x 45cm.

How Many Runner Bean Plants can you fit in a Single Container?

This depends very much on the size of container. Runner beans should be placed around 30cm apart when planting. The larger the container, the more plants you can grow!

Can I Grow Runner Beans in Grow Bags?

Although it is possible, grow bags are not ideal for growing runner beans. The small volume of compost within grow bags means that as well as holding less nutrients, there will be limited space for root development and it may be difficult to maintain a high enough moisture content for the plant to thrive.

If you do use a grow bag, try and get as deep a grow bag as possible. Also be aware that you may need to feed and water more regularly than if you were growing in a large container.

Do Runner Beans Require Support?

Runner beans are climbers so will require some sort of support structure. The most popular support options are bamboo canes or trellis.

Bamboo Cane Support

Runner beans are heavy croppers so be sure that whatever support you use is strong enough to hold the weight of the beans!

When using bamboo canes especially, – the deeper and larger the container, the easier it is to create a sturdy support structure. This brings us to another drawback of using grow bags: due to their limited depth you are likely to run into issues providing adequate support.

Follow this link to shop for runner bean support frames on Amazon.

How Tall do Runner Beans Grow?

Climbing varieties of runner beans can easily reach 3 metres or more in height.

Once the plant reaches the top of the trellis or cane, it is best practice to “pinch out” the top of the runner bean plant to stop it getting any taller. If you don’t pinch out the plant at the top the vines will grow and grow an you will just end up with a tangled mess!

Runner Bean Ready to “Pinch Out”

Pinching out allows the plant to concentrate energy on flower and bean production. This will maximise the yield and will cause the plant to take on a thicker, bushier appearance.

What Soil Conditions and Aspect do Runner Beans Prefer?

It is possible to start runner beans off using a multi purpose compost or soil mix, but as we have already mentioned, when growing in containers it will likely be necessary to add additional feed in order to maintain the required levels of nutrients. Adding liquid tomato feed every few weeks to runner beans once the plant begins to flower is a good idea as tomato feed is high in potassium.

In terms of position, although they will tolerate some shade, runner beans need exposure to sun – ideally at least 6 hours per day. The soil needs to be kept moist throughout the day – large, deep containers will help with this. Mulching around the base of the runner beans will also help keep moisture loss to a minimum. However, in very hot weather you will probably find that you will to water every day!

Runner beans also need to be sheltered from the wind wherever possible, as it has the potential to shred and damage the leaves of the plant.

When is the Best Time to sow Runner Beans?

Runner beans will not survive frost. If you are sowing directly into your container outdoors, you will need to wait for the last frost to pass – typically towards the end of May in the UK.

Alternatively, for an earlier crop, you could sow indoors first before moving the plants outdoors once the threat of frost has passed.

Sowing SummaryRunner Bean
Sow indoors for an earlier cropApril to May
Move from indoors to outdoorsMay onwards (avoiding frost)
Sow outdoorsMay to July (once soil has warmed, will not survive frost)

When Will Runner Beans be Ready for Harvest?

Runner beans will be ready to pick after approximately 10 to 12 weeks.

It is best to pick them when they are around 15 – 20cm in length. If you leave them too long they will become tough and stringy.

The key is to keep picking them regularly – every few days. The benefits of this are two fold. Regular picking will ensure that you don’t allow any beans to become past their best and it will also encourage stronger growth and more beans!

Harvest SummaryRunner Beans
HarvestCrop after approximately 10 – 12 weeks: from July through to October

In Conclusion

So, now you know more about how to create the best conditions for growing runner beans in containers, you can hopefully look forward to bumper crops later in the year!