This week I’ve had a lot of questions from my garden coaching clients about containers and what to grow, so I thought I’d share a little container gardening tutorial. I’ve also written about container gardening before. We’ve also discussed container gardening on the Gardenangelists podcast.
If you read and listen to these and want individual help, just contact me at firstname.lastname@example.org for a personal gardening coaching appointment.
Container gardening isn’t difficult, but it does take a little planning, starting with the containers you buy.
Here are some choices with their pluses and minuses:
- Glazed ceramic. I like glazed ceramic containers that have glazed rims. These are nearly freeze-proof in Oklahoma because moisture can’t get into the container as easily as it can if they are terra cotta or have an unglazed rim.
- Terra cotta needs more frequent watering because it is more porous. Also, terra cotta will crack over winter in our climate. I don’t grow my summer plants in terra cotta because I can’t keep them watered well enough. I use terra cotta for my pelargoniums (geraniums) and put them in partial shade. Choose Italian terra cotta if you can find it.
- Plastic containers can be good in a pinch. They are inexpensive, lightweight, and easy to move around. However, they don’t last long because they become faded and brittle in our sunlight. Still, there are some nice plastic containers out there.
- Fabric pots. I like fabric pots with handles like Smart Pots and grow most of my vegetables in them. They last for several seasons.
- Metal containers. Nothing beats the silvery goodness and contemporary charm of galvanized steel stock tanks or lead-free metal containers for modern architectural style. They make great small ponds, too.
- Upcycled containers. I’ve seen plants grown in everything from bathtubs to plastic storage bins. Almost anything works. Just be sure to drill drainage holes.
Whatever type of containers you pick, it’s good to be aware of the pluses and minuses of each material before you choose. I talk more about this in my book, The 20-30 Something Garden Guide: A No-Fuss, Down and Dirty, Gardening 101 for Anyone Who Wants to Grow Stuff.
Bigger is better in a hot climate.
Your pots should be at least 18 to 24 inches wide and 12 to 16 inches deep to provide plenty of room for your plants, but I think you should go even bigger if possible. One benefit to using larger containers is they don’t dry out as quickly as smaller ones. Small pots can look nice tucked into small spaces, though.
The next thing to consider is color.
If you choose dark brown containers, they will ground your plants by mimicking the earth beneath them. Dark brown also looks great with almost any plant color. If you use blue, you are mimicking the color of the sky. Turquoise and cobalt blue pots are very dramatic, with turquoise looking great next to a swimming pool. Concrete pots do, also. Green pots can be problematic because they are the same shade as most foliage. Coleus and other bright foliage plants are great in almost any colored pot.
Before you buy the containers, how will you water them?
I get many questions about my drip irrigation system. I have timers, a backflow regulator, tubing, and adjustable drip emitters for my pots. Originally, I bought a drip irrigation kit online. You can also find these locally. Over time, I’ve supplemented with additional drip emitters, tubing, and timers from Ewing Irrigation and Landscape Supply in Oklahoma City. I wouldn’t water my containers any other way.
Containers are two zones colder than your climate zone.
If you’re going to overwinter shrubs like roses or blueberries in containers, they must be hardy enough for two zones colder than your winter climate zone. I live in the country, which already makes my weather cooler, and some of my pots are on top of an elevated deck, making the plants in them even colder. These are all things to consider, and before winter, I often move my containers with roses and other overwintered plants up next to the house to provide a little additional warmth and protection.
Most potting soils are mixtures of several ingredients. Good quality potting mixes can be found at your local nursery or box store. In recent years, there’s been a move away from the main ingredient, peat moss, to coconut coir, the fibers from the inner shell of the coconut, which is considered more sustainable.
You will also see bags of garden soil or raised bed soil but don’t use either of these in your containers because they don’t drain well. Also, don’t use garden dirt because it has weed seeds and bacteria and isn’t free draining either. Container mixes are formulated to be light in texture, free of disease and weed seeds, and provide good drainage.
While it’s very expensive, I love Happy Frog potting soil. This company also makes a coconut coir potting mix called Coco Loco. I also use the potting soil from TLC Nursery, a local nursery, and other organic potting soils. Take the time to figure out which potting soil you like best. If you use coir potting mixes, they retain water better and don’t need as much irrigation, especially in cooler weather. At least, that’s what I’ve noticed in my garden when I’ve used them.
Replace potting soil?
Another thing, I always get asked if I replace my potting soil every year. I do not. For my ornamental plants, I replace the top 1/3 of potting soil each spring so that they have fresh nutrients. Most of that comes out of the pot with the roots of the previous year’s plants.
For my tomatoes and other vegetables, I try to switch around the plants in the containers and add some organic fertilizer and compost each spring. I don’t grow tomato plants in the same potting soil year after year because diseases and other stuff will build up in the soil. I use the old potting soil in my cut flower bed or grow different vegetables in it.
More on containers next time
When I started to write about the plants for containers, I realized I had a whole other post. I’ll post about them next time in part two of this series. For now, go out and choose your containers and potting soil wisely. I saw some nice glazed pots at HomeGoods and at Westlake Hardware for those of you who are local.
In the meantime, I posted before about the best plants for summer containers. There’s more inspiration in container madness, a post for GBBD.
Also, don’t plant those containers with summer plants like tropicals until after April 20.
Talk to you soon!
That was great. Answered a lot of questions. I usually don’t do containers but am going to try a number of different plants in containers this summer.
Good and helpful information, Dee! Enjoyed reading this article. Lots ow good information.
Thank you Decah. I’m so glad it’s helpful.~~Dee
Just when I’d resolved to grow fewer containers this year . . . . I love the look of terracotta/clay, but they do dry out fast in the summer. I have a few plastic pots that fit down perfectly inside of my clay pots and that’s what I use. I also use them I like terracotta with pelargoniums because I tend to overwater, and just off my back porch where I see the plants every day and can gauge whether or not they need to be watered.
Hi Melissa, I also have my pelargoniums in terra cotta because I love how they look. I put them on a staging area on the north side of the garage in summer. I do have a couple of fancy terra cotta thrown pots from Wakefield, and I have roses in them. I have them over by the potager because it’s traditional and beautiful. ~~Dee
Great information, Dee!! For any climate!
Thanks Carol. A lot of this information was part of my book. I just rewrote it and added some more recent thoughts. ~~Dee
So many great ideas. I’m definitely bookmarking this one Dee. Thank you! P.S. I love TLC’s organic potting soil too.
Dana, TLC has fabulous potting soil. ~~Dee
Such great information! I love the cobalt blue pots and have a few of them. Thanks Dee!
Hi Sonia, I love blue so I have several of them too mostly on the back deck. I did give some to a friend a few years ago because I had too many. I need to downsize my number of containers again. I’ll think about that this summer.~~Dee