One Hundred Dollars a Month reader, Barbara, recently sent in a question about the soil in my containers. Not only is the question pretty timely, given that it is almost time to address the containers on my patio, but I thought it might be something some of my other readers want to know.
Barbara wrote,
Hi Mavis,
I have a quick question for you about your garden containers that you use on a patio. Do you put new potting soil in them each year or do you take out what has died and add more soil to it? Some containers I have are larger and I am trying to keep from having to put all new soil which gets to add up in cost. I know that when you moved you are probably starting fresh.Thanks for your help.
Barbara
I typically change out my soil once a year and toss the old potting soil into my vegetable garden. I have found that my pots simply do better with fresh soil each year. A lot of times, when I pull out the soil from the previous year, there are significant roots, which limit how well then next year’s plantings can do. I feel pretty good about just tossing the old soil into my beds, because I typically mix in some homemade compost, and really work the soil in. My beds seem to do great with this process. Also, I usually make my own potting soil, which is waaaay more cost effective than buying the pre-bagged mix.
If you have giant pots and don’t want to commit to filling them year after year, just add old gallon sized milk jugs to the bottom of containers. It will take up some of the space in the bottom of you pots, and limit how much soil you have to add each year. {The only time I would caution against this, is if you are growing something that likes to have nice deep roots, like tomatoes, in your containers.}
If you are only growing flowers, you can also just replace about 1/3 of your soil each year, mixing the new in with the old, and making sure to remove roots from the previous year. {You may want to consider a high quality organic fertilizer a couple of times during the growing season if you choose the 1/3 soil replacement method.}
However you decide to change out your soil, the key to successful container gardening IS healthy soil. The plants are totally dependent on the soil you provide them in the small space to grow. They can’t draw from the earth around them, so taking the extra step to make sure they have nutrient rich soil each year really will show in the final product.
Hope that helps. Great question, Barbara.
~Mavis
tc says
As many of our big pots have shrubs or other plants I don’t want to disturb I add a top dressing of compost at least 3 times a year or as the soil settles. It seems to work, would like Mavis’s comment on whether she thinks this is good enough.
We have grape vines in large pots and honeysuckle so we can’t just empty them each year
Tina says
I’ve put compost in my pots each season and have some over 20 years old that are doing very well still.
Tisha says
Another way to use less soil in large pots is to place broken branches in the bottom, even better if they are dry. They will also hold moisture, too.
JoAnn C. says
I put all my old potting soil into my compost heap at the end of the season. That way the old roots in the potting soil decompose and the soil itself helps the other items in the compost to decompose faster. By the time spring rolls around, that compost is ready to go into the vegetable garden. No waste!
Connie Wheeler says
I remove just the top 1/3 to 1/2 and recycle it into garden beds or, mix it half and half with new potting soil so I don’t have to buy a ton of new potting soil every year. I found out the hard way that you have to be sure the potting soil you buy is not the kind made out of almost all peat moss cuz once peat moss dries out, you can rarely get moisture back in it again. My plants kept drying out and even watering wasn’t helping so I asked some experts about it and yep, the potting soil I had purchased was PLANTING MIX which is almost all peat moss. You want to buy POTTING SOIL instead which does have some peat moss in it. Of course the best is the good ol’ “organic” stuff you can get from farners!
Ellen in Clackamas says
I have a lot of my garden in pots and for the small ones (1 gal) I usually take out all the soil and compost it. The bigger ones (5 gal and up) I just take out the top half and refill with new soil. I do this with flowers and vegetables. Also, many of tomato plants are in those pots and I have always had good luck with them. And with all of the pots I add a water-soluble fertilizer every couple of weeks.
Ronnica, Striving Stewardess says
I don’t change out my soil (I don’t have a garden, apart from my containers), but I am always adding more pots, so I move the “old” soil around so that I’m not planting the same thing in the same soil and all containers get 1/3 to 1/2 filled with new soil. I suppose there will be a time when I don’t add any more pots…but I’ll probably be in a house by that point!
mary e. charleston says
thank you i live in a senior apartment have containers s i cannot afford to purchase new soil every year so i will take some out i have just purchase new compost and organic container soil found on line thank you
Camille Xin says
Barbara, what do you mean by “remove roots from the previous year”, do you mean we have to dig out the plants/flowers/shrubs each spring and cut out their bottom roots? there would be too much work! we have lots of pots and long planters with big shrubs and small trees. some of them the roots grow so big and even to the top of the pot. I can’t really change much of the soil. I don’t know what to do as I can’t just start to cut their roots either.
I guess I just have to keep on add compost or water soluble fertilizer every week or two?
kathy says
I had tomatoes in a big 15 gallon pot. They got mildew, Do I have to change out the potting soil? What do I have to do if anything to the containers?
Mavis Butterfield says
I would add new soil to your pots after scrubbing the insides down and cleaning them thoroughly.