Drainage in Pots and Containers

[Ron]

I have always used a layer of gravel or larger stones in the bottom of a pot ot container to aid drainage. When I was emptying containers that had had plants in them for a few years that I was disposing of, I noticed that the bottom layer was almost solid in many cases and didn't seem to be good for drainage at all. This led me to do a little research online to see if there was a better material to use. Although there were many suggestions, I came upon a site with a different perspective. There it suggested that using any material whatsoever as a drainage layer was a bad idea. www.todayshomeowner.com/garden-myth-putting-gravel-in-pots-and-containers/

What is your experience?

This explains it even better: puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/container-drainage.pdf

[andy]

I've used anything from a few crocks to pieces of polystyrene. The problem with the latter is that it can make the pot very light....ideal for moving it about and saving soil but it makes the pot quite lightweight and prone to blowing over.

It's always good practice to remove any long term plants grown in containers (shrubs, trees etc) and to remove about 1/3 of the old soil and roots and replace with fresh stuff every 3 years.

[Ron]

Feb 11, 2017 7:02:23 GMT andy said:

I've used anything from a few crocks to pieces of polystyrene. The problem with the latter is that it can make the pot very light....ideal for moving it about and saving soil but it makes the pot quite lightweight and prone to blowing over.

It's always good practice to remove any long term plants grown in containers (shrubs, trees etc) and to remove about 1/3 of the old soil and roots and replace with fresh stuff every 3 years.

Yes, I've done that andy, refreshing the compost. Its the bottom layer though that they are talking about which can't be replaced or amended without repotting. Have a look at the 2nd link and see what you think.

[andy]

I think we sometimes get a little too deep in things like this and we forget the basics...such as is the plant(s) in the container doing well? If the plant is growing nicely and looking good, then why try to fix it if it's not broken.

Ok, if a plant is showing signs of distress, then we would obviously look for reasons....nutrient difficiency, over/under watering, wrong situation, wrong type of soil, pests and diseases etc etc. but if a plant is growing strong and healthy, the compacted layer at the bottom might be a good thing.

Personally, in 35 years of being a profesional gardener and nurseryman, i can't say i've ever noticed the bottom layer being compacted. I suppose a few inches of 50/50 soil, grit at the bottom might help but to be honest, plants are used to growing in hard, compacted soil in the ground.

[Ron]

Thanks, andy , yes, I get your drift. It is a fault of mine I suppose, reading too much into the theory which is often subjective anyway. Best to just get on with it!

Though probably not today, it's snowing.

[blc]

I put mulch at the bottom. If I have some large stones I try and put them near or on the hole (especially when the stone is irregular shaped) to help let excess water drain. I use miracle grow moisture control potting soil and mix in about 50/50 of cactus/citrus soil. Its a lot lighter.

I prefer using the larger stones. I wouldn't worry so much about the bottom being solid, as long as it is draining. jmo

[blc]

Feb 11, 2017 6:54:23 GMT Ron said:

I have always used a layer of gravel or larger stones in the bottom of a pot ot container to aid drainage. When I was emptying containers that had had plants in them for a few years that I was disposing of, I noticed that the bottom layer was almost solid in many cases and didn't seem to be good for drainage at all. This led me to do a little research online to see if there was a better material to use. Although there were many suggestions, I came upon a site with a different perspective. There it suggested that using any material whatsoever as a drainage layer was a bad idea. www.todayshomeowner.com/garden-myth-putting-gravel-in-pots-and-containers/

What is your experience?

This explains it even better: puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/container-drainage.pdf

Hmmm, I usually put larger stones over the holes so they don't plug with dirt. This year I used some mulch with bigger chunks of wood. Thinking on it, that might encourage the wood to retain the water. Might not have been a good idea. I thought it might help with nutrients.

Seems I've read that sand is great for filtering water so maybe it would be the best for drainage. But how do you keep it from going out the drainage holes?

[Ron]

blc, I too use larger stones now, just a few around the drainage hole, it seems to work fine. When I'm potting on though rather than using containers, I don't use anything. I just put in a layer of compost and compact it down before filling the rest of the pot. As Andy said, plants are used to growing in compacted soil and it seems to work. (I tend to follow Andy's advice because he works as a gardener and knows his stuff.)

[owdboggy]

I put a piece of the wire gauze used for mending cars over the hole in the clay pots to keep worms out as far as possible and then fill up with compost, no other drainage material. Never had any trouble with waterlogging by doing that. In the big containers I do fill up with bits of polystyrene to save on compost though, not for drainage.

[Ron]

I have a useful tip for growing plants in large pots where you use them for the height rather than the plants needing such a large space. You can buy round trays to go under the pots and if you buy one smaller than the pot so that it fits 8 to 12 inches down from the top and push that into it, you can grow plants on top of that. Put water into the bottom of the pot to form a resevoir and make small holes in the tray. The plants will form specialised roots that go down into the water and will grow better for it.

[blc]

Jul 21, 2017 11:20:58 GMT Ron said:

I have a useful tip for growing plants in large pots where you use them for the height rather than the plants needing such a large space. You can buy round trays to go under the pots and if you buy one smaller than the pot so that it fits 8 to 12 inches down from the top and push that into it, you can grow plants on top of that. Put water into the bottom of the pot to form a resevoir and make small holes in the tray. The plants will form specialised roots that go down into the water and will grow better for it.

That's exactly what I did last year! lol Saves using a ton of dirt. Even still the containers were heavy, even using a wheeled plant stand.

[Ron]

I had a couple when I lived in Yarnfield, blc, the water collected in the bottom when it rained which made them very heavy.

[blc]

Jul 21, 2017 6:29:17 GMT Ron said:

blc , I too use larger stones now, just a few around the drainage hole, it seems to work fine. When I'm potting on though rather than using containers, I don't use anything. I just put in a layer of compost and compact it down before filling the rest of the pot. As Andy said, plants are used to growing in compacted soil and it seems to work. (I tend to follow Andy's advice because he works as a gardener and knows his stuff.)

This is true, in the wild no one is tilling and loosening the soil. The plants we are planting in the ground I still add a little mulch, because we don't have compost

Jul 21, 2017 15:40:57 GMT Ron said:

I had a couple when I lived in Yarnfield, blc , the water collected in the bottom when it rained which made them very heavy.

I didn't use my large containers this year. We moved into this house almost 2 years ago. At the time we had so much clean up to do around the house that I used the containers. We had thistles by the front door that were about 6 ft tall. Some sort of bramble was growing in front of the house that was like thick vines. The side of the house was so overgrown that my husband didn't even know there was a sidewalk and stairs there! This was his sister's home and she had passed away suddenly and we decided to buy the home. After my brother in law passed away, I guess the kids couldn't be bothered to help take care of the place.

We are still adding landscaping. My husband just digs a hole where I want a plant. Irks me because I know the soil should be tilled a bit, but you take what you get, lol.

On the deck I have a lot of container pots. Most were meant to be hangers or to sit on the railing, so sitting them on the deck, they didn't drain well, so we put pieces of wood under them to lift them enough to allow for better drainage.

We usually just did cherry tomatoes but this year we added roma, health kick, thai chili peppers, pickles, cucumbers, yellow bell peppers, bush green beans, summer squash, zucchini, sugar baby watermelons, then I added an acorn squash and a cantaloupe. Plus the kale, chard and flowering cabbage for the groundhog. Those are on the railing though. That doesn't even take into account the flowers! lol Plants along nearly the whole perimeter of the deck! I put the clear plant bases under a lot of them and wonder if that creates its own problems.  Too much water, contaminated water?