Container Gardening - Environmental Factors

Wiese Acres Container Gardens

One of the things I've learned from speaking with a lot of gardeners from all across the country is that we all face challenges of one kind or another.  I teach a class whose description begins:  "It's often said, if you can garden in North Dakota, you can garden anywhere."  I'll talk about the challenges of gardening in our climate and invariably, someone will say, "But, let me tell you about gardening in (insert name of their home)..." 

There are some universal challenges when doing container gardening, that's for sure.  Light, temperature, and wind need to be paid attention to if you want to successfully container garden.  All three of these need to be considered before you choose the plants for your container garden. 

Proper light for your container gardens may be the easiest to master.  Containers are generally pretty portable, so if your container is in the perfect lighting conditions in the spring, but not quite right for the depths of summer, you can simply adjust the location of your container.  That is the beauty of having larger containers with wheeled bases or that can rest on a dolly.

Temperature may be a bit harder to control, but there are some tricks you can use to make temperature and your plants more compatible.  In climates where frost looms before you are finished enjoying your container gardens, those on dollies or wheeled bases are easily moved inside to a safe location.  Others generally lend themselves well to being covered with a blanket.  If necessary, small, tall dowels can be inserted along the edges of the pot to hold the frost blanket off the plants, protecting them from weight damage and creating a nice, warm coccon for them inside the blanket.

In areas where summers are very hot, using light colored, large sized containers helps keep the soil, and therefore the roots of the plants, cooler.  In large containers, you can spray the inside of the container with a spray foam insulation product to add another layer of protection.  The spray foam insulation is available at most home centers in small aerosol cans that are usually quite reasonably priced.  Be careful to maintain the drainage or, in the case of self-watering containers, the water wicking, ability of the container.

Dark colored containers may be beautiful and fit nicely with your decor, but they are harder on your plants.  When a dark-colored container sets in full summer sun, the soil can become so hot that it actually scorches the roots of the plants.   Ideally, dark colored containers should be used in shadier, cooler locations.  If you need to use one in a full sun location, consider growing a light colored trailing plant such as dichondra or licorice vine that will grow densely enough to shade the container.  If you don't wish to use a trailing plant, herbs and succulents will tolerate much hotter soil conditions and may be an option for the dark planters.

The hotter the temperature and the warmer your soil gets, the more water the container is going to need to keep the soil from drying out.  Containers in full sun may require watering multiple times on a hot, sunny, and windy day.

Wind is a problem not only with drying out, but also can cause plant damage or even blow the container over.  Before the trees grew large enough to provide some windbreak at Wiese Acres, I would get home from work to find empty containers littering the driveway and the dried out soil and plant mass that had been in them somewhere further away.  Trees and larger, heavier containers have solved that issue for me, but the wind damage to the foliage can still be a problem.

Plants, especially those with large leaves, can be damaged by strong winds.  Flowers and buds can become dried out to the point where they drop or fail to open.  Stems can be broken off completely.  The best way to deal with this is to relocate the containers to an area that is protected from the wind, either closer to the buildings, protected by a fence or trees, or moved inside on those days when high winds are predicted.  And, if none of those strategies work, you may just need to give up on growing certain plants.  I love the majestic look of cannas but there is no place in my yard that receives enough sun and is still protected from the wind.  So, I have learned to live without them.  There are lots of other plants to choose from that are more ideally suited to my location.

Our next container gardening blog will be about strategies for choosing the right plants for your containers, but that won't be until Monday, April 15.  This weekend is the huge Dakota Garden Expo and I will be busy with that this evening and all day Saturday.  Sunday I will be recovering but will be ready to blog away again by Monday.  I will be posting the handouts from my session on the blog.