This is the second post of an ongoing blog series on Married to Plants about palm tree growing tips. The first post was about palm tree mounding. This post is on the exceptional Stuewe and Sons treepots and the benefits of using their containers with palm cultivation. Because your choice of container is one of the most important aspects in successfully growing plants, careful consideration should be made. Not only does your container choice directly affect water and nutrient levels for your plants, but it also dictates how you manage your potting-up cycle for continuing cultivation success. Since 1982, Stuewe and Sons has been helping achieve this with what I consider to be the best containers available.

Before getting into the benefits of Stuewe treepots themselves, we must first understand how water works once introduced inside a container. To begin with, there are two forces that cause water movement through soil: gravity and capillary action. Gravity in a container is constant like everywhere on Earth. However, the gravitational potential is greater for water at the top of the container than it is for water at the bottom. So there is more pull farther up the pot. Capillary action is the ability of water to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. Dip a paper towel into a glass of water, watch the water move up the towel. That is capillary action. Water does the same thing with soil in containers.

What you should get out of this is that the gravitational potential is pulling the water down the pot, while capillary action is lifting it up. So how high will water travel up the soil in a container? Answer: to the point where gravity cancels it out. It is at this point where the capillary pull of the soil equals the gravitational potential and where the water in a container will not drain and becomes “perched.” This perched table is what can also be called the “saturation point” within the container. There is always a saturation point in a container. The most important thing to take from all this is that the size of the container does not affect the height at which the saturation point occurs. It will remain the same for all container sizes that are using the same potting medium as the diagram below shows.

Even though every container has a saturation point, there are a few factors that will affect it. One is the potting medium (which I will not get into in this post) and how “draining” it is. The other two ways water is removed from a pot are through evaporation and by the plant taking up water. In other words, if you stop watering, available H2O will eventually be removed from a pot from other factors. However, most palm tree growers and nurserymen don’t wait that long between watering cycles, so knowing and understanding the saturation levels in a pot become key.

Why is this beneficial in container culture? Simply put, water and air cannot share the same space in the soil. So below the saturation point the growing medium has much less aeration. This limits beneficial gas exchange and also can lead to root problems like rot. A container with the saturation point farther down provides for more available, usable soil for roots to grow healthy thanks to greater aeration. As discussed, two things control the depth of this saturated level. Your container height and the type of growing medium. Reading the information just presented and in looking at the graph above, it is pretty easy to conclude that tall containers are a much better choice for palm cultivation over traditional squat containers when the same growing medium is used in each. This is why I use Stuewe and Sons treepots when growing palms in containers. Years ago I moved away from traditional squat pots to my Stuewe treepots, and the results have been quite dramatic in terms of overall plant health and growth. Healthy plants with a robust, deep root mass are now the norm, as you see below.

There are a few more benefits to using deeper containers, and in particular the Stuewe and Sons treepots. For starters, Stuewe and Sons containers have fluted insides verses the smooth insides of the traditional squat pots. This helps prevent root circling, directing roots downward toward the holes in the walls and the bottom of the container. You can see in the photos below a great example of how roots look when coming out of a Stuewe 3-gallon treepot. The roots have been channeled down the pot and you’ll find very little root wrapping.

Below is a “Golden Form” of Dypsis lutescens being potted up. If you look closely you can see all the main roots being channeled down along the fluted sides. Once the roots reach the bottom and are limited in how much they can wrap, it forces the palm to make more secondary roots. As an example, you can see many secondary roots coming off that main root to the far right in the palm below.

Another benefit of Stuewe and Sons treepots is that I can store more plants in my greenhouse. Thanks to the smaller footprint of the treepots over squat pots, they can be placed closer together. So these Stuewe treepots allow me to save much needed space in an ever-increasingly congested greenhouse. You can see in the photos below that as I add more plants to the greenhouse, I can push these current plants closer together. I couldn’t have this many palm trees in squat pots on this table.

As I mentioned earlier in the post, container consideration will also dictate how you manage your potting-up cycle for continuing cultivation success. Stuewe & Sons treepots allow for excellent progression between the small seedling bands and into the larger 15- and 25-gallon pots. The first I use is the “CP59R.” It is 5 inches round, 9.5 inches tall and has 0.7 gallons of volume. It is perfect for potting up my small seedlings I grow in bands. From the CP59R, I move right to the “TP915R.” It is 9 inches round, 15.5 inches tall and has 3.2 gallons of volume. Details on both these pots can be found by clicking here.

From the TP915R I go right into a 15-gallon pot. In many cases you wouldn’t be able to move from a traditional squat 3-gallon pot to a 15, as you would be “over-potting.” The danger of over-potting is that the saturation zone would be too far down in a 15-gallon pot, so you risk the change of your plant drying out if you are not watching the soil moisture levels carefully until the roots reach the saturation zone in that 15-gallon pot. You do not have to worry about this when using the Stuewe and Sons treepots, as the pot is deep enough already, so when you put the plant into a 15-gallon, the roots will already be in the saturation zone of that much larger pot. Doing things this way allows me to skip using the 7-gallon pot many nurseries have to use when going from a Band->1->3->7->15-gallon squat pot progression.

One final benefit to consider when choosing Stuewe treepots over traditional squat pots is the benefit of the deeper roots you’ll have when planting your palm straight into the ground instead of moving to a 15-gallon pot. Saturation zones don’t just exist in your container, they are also found in your garden soil. A plant with an already deeper root mass will better handle the early stresses that a plant can feel when moving from the container to the ground. Simply put, the deeper roots will have better access to the water in your garden’s soil. This helps ensure your newly planted palm won’t dry out, it helps reduce burn, and here in Southern California, helps reduce stress from dry, hot Santa Ana winds. Remember too, a healthy palm will be much better at fighting off insect and fungal attacks as well.

If there is one negative about Stuewe treepots, it is that they are considerably more expensive than standard squat containers. Prices can be 3-4 times more per pot and it is for this reason you don’t see them used at most nurseries. However, for hobbyists looking to grow much happier palm trees, I find the cost difference to be trivial. Most palm trees are not fast growing. We hobbyists can end up investing a lot of time into growing our prized plants. Why cut cost with something as important as container choice and avoid all the benefits I laid out? There have been what I consider a few game-changing choices I have made in my plant culture that produced considerably noticeable results. Buying Stuewe and Sons treepots was certainly one of those.

Tagged: Dypsis, Gardening Tips, Palm Trees

October 20, 2016