Best soil for bamboo. How to improve yours

Best soil for bamboo. How to improve yours

You can see bamboo grow all over the world in all kinds of conditions: clay-heavy soils, sandy and loamy soils, as well as rocky soils in mountain regions.

Bamboo is not too picky and grows in different types of soil.

That said, some bamboos, for example, Moso, are rather particular about the growing conditions they prefer. Moso requires a certain soil type, pH, moisture, and even slope for best growth results. 

And – while bamboo can grow in various soils, the better the conditions, the better, faster, and healthier the plants will grow. 

Best soil for best results

Whether you grow your bamboo in-ground or in containers, having appropriate soil mixture is the first step to beautiful and healthy plants.

Good soil composition allows for proper drainage and optimal levels of nutrients. 

Soil for container growing

If you plan to grow your bamboo in containers, make sure to use a good potting mix. Many commercial potting or nursery mixes are adequate as they are but some are not.

Growing bamboo in containers means that the only nutrients available for the plant are the ones you provide them with. So why not get the best option? 

Bamboo experts at Lewis Bamboo recommend Miracle-Gro® Moisture Control® Potting Mix as the best option for container bamboo. 

Their recommendation for the best soil mix for container bamboo is to mix these three ingredients to get the best growth: 

75% Miracle-Gro® Moisture Control® Potting Mix

20% Black Kow Composted Manure (or other well composted manure)

5% Biochar

These proportions of soil mixture contain the optimal amount of nutrients and ensure good drainage which is really important. You don’t want to drown and rot the bamboo by accident. 

What role do these ingredients of soil mixture play? 

Manure: it acts as a slow-release fertilizer. Mixing 20% composted manure ensures long term nutrient supply and adds beneficial bacteria to the mixture. 

There is no “best of best” type of manure. Any variety of composted manure is good. However, always use composted manure and not fresh manure! Any type of manure will give the fertilizing bamboo needs, be it cow, horse, or any other manure available to you, it’s all great as long as it’s fully composted. 

Biochar: it acts like a sponge in the soil mixture allowing for proper nutrient absorption. It increases retention of plant nutrients like phosphorous and nitrogen, and reduces the need for fertilization.

Having 5% of biochar in the soil mixture is optimal. No need to add too much of it. 

Good enough potting mixes

Most major retailers like Home Depot and similar have topsoil and composted manure available. They typically are sold in 50lb bags but other sizes are available of course. 

Many of the potting mixes are good enough to use for planting bamboo.

How to choose the right bags of soil at the shop?

Ideally look for a nursery grade potting soil. Avoid bagged soil that’s full of light filler material. Those types of mixes don`t compress well and dry out very fast.

Do not buy landscape mixes if you plan to grow container bamboo. A good vegetable mix with compost is a much better choice. 

An appropriate soil mix drains well and at the same time retains moisture. 

Most mixes contain both organic and inorganic elements. Both have their role to play in ensuring great growing conditions for plants. 

Sand, volcanic cinders, and perlite are all nice stable inorganic components. Sand is the cheapest of them but is good for airflow and drainage. Cinders and perlite are pricier but are exceptional for drainage at the same time as holding the necessary water. 

Compost and peat are good organic components to look for in soil.  A small proportion of loam or clay for extra micronutrients is also a sign of a decent mix. 

The texture is more important than nutritional qualities when buying a base for a potting mix. You can easily add compost and fertilizer to any soil with good texture – for bamboo that is loosely textured.

Soil for in-ground growing

Most bamboos evolved in forest-like environments and slightly acidic soils before moving to our backyards as accent pieces and privacy screens.

Now, as I already mentioned, bamboo can survive in all kinds of soil conditions and soil types. However, it thrives in slightly moist soil that is light and loosely textured, rich with nutrients and has good drainage. 

Loamy Soil

Bamboo thrives in loamy soil. This type of soil combines sand, silt and clay and retains moisture without waterlogging. 

Air pockets in loamy soil allow bamboo roots and rhizomes to remain oxygenated, the soil’s water retention prevents drought stress. It also holds nutrients well.

Loamy soil feels soft and crumbly to touch and is easy to work with in different moisture conditions. 

There is no exact proportion that defines how much sand, silt and clay there must be for it to be classed as loamy soil. 

It can be roughly equal amounts of all three. Another variation – half of sand, about 30 – 40% of silt, and 10 – 20% clay. Some say that loam soil is about equal parts of sand and silt and a little less clay. 

For home gardeners, perfect proportions are impossible and unnecessary anyway. We can leave that to scientists and commercial farmers. 

For regular people it’s enough to have a rough idea of what loamy soil contains and feels like. 

Ph

Most bamboo prefer to grow in moderately acidic soil, with a pH of 6.5 to under neutral 7. 

If you have alkaline soil, it does not mean you can`t grow bamboo. To make it more acidic, amend it with adding sulfur or other acid fertilizer. 

For overly acidic soils with pH of 5.5 or lower, you can add lime to reduce acidity. 

If you don’t want to change the pH levels of your soil, you can also choose a more versatile bamboo, for example, Giant timber bamboo (Bambusa oldhamii). It grows in USDA zones 8 to 11, and tolerates any soil type, from highly acidic to highly alkaline. 

Improving soil

So, what to do if your garden area does not have the perfect loamy well-drained soil that bamboo plants love?

Improve it!

There are ways to work with what you have and make it better. 

Bamboo roots are relatively shallow, so the good news is – if you are amending your native soil, there is no need to go deeper than about a foot in. 

If your soil is less than optimal, the extra time and expense of improving it are usually really worth the effort when you get to grow healthier plants faster.

Improving drainage

The vast majority of bamboo don’t like to grow in wet and soggy conditions. If your property seems to be on the wet side, one of the “water bamboos” such as Phyllostachys heterclada, atrovaginata, or parvifolia, could be best suited for you.

Clay heavy soils are rich in minerals and trace elements but are typically the ones with drainage problems. Most bamboos suffer root damage if submerged in water for several weeks at a time. 

They can be improved to provide better drainage if you add sand and organic materials like compost to it. The heavier the soil, the more sand and organic material needs to be added. 

But generally you can think of it like this – to 3 parts of your native clay heavy soil, add 1 part organic material (like compost) and 1 part sand.  And mix it all together. 

In some cases ditching around the planting is a good solution to improve drainage. 

For container bamboo

Good drainage is important for container bamboo. Thankfully it is easy to achieve.

When planting your bamboo, first make sure there are drainage holes in your container, then put a 2 to 5 inches deep layer of coarse river sand at the bottom of the container. 

That is all you need, when you have the sand layer, you can fill the container with your chosen potting mix and plants. 

Fertilizing

It is recommended to fertilize bamboo twice a year for best growth results.

Once in early spring to encourage new growth, and once during the middle of the growing season to replace any nutrients that are being depleted.

A slow release fertilizer like this one with a 19-6-12 formula is good for bamboo. 

Adding compost to loamy soil

You already know that bamboo grows well in loamy soils because they have good aeration and drainage. 

However, as mentioned, loamy soil consists of sand, silt and clay. None of those are organic materials. This means that loamy soils need to be improved by adding compost (or comparable organic material like peat, manure, bark chips) for nutrition. Compost also helps retain moisture and acidity of the soil.

Typically a good proportion is to add 1 part compost to 3 parts of native loamy soil.

Transplanting and repotting

For container bamboos, it is crucial to be repotted about once every 3 years. Sometimes even sooner, depending on how big the container is. 

When growing in a container for too long, bamboo can get root-bound and start struggling. To keep it looking its best, repot it regularly.  

And of course, every time you repot, check the quality of soil and don`t forget the layer for drainage. 

Transplanting in-ground bamboo is not required to keep the plants healthy, but it can be done if you wish to propagate it and give it to your friends or make your privacy screen longer or thicker. 

Featured image: Fertile Soil by Editions Photoart, Flickr, CC BY 2.0