How to prevent drainage from large pots on concrete

[Lori Phipps]

We have several large pots on concrete and are having a difficult time with drainage when the plants are watered. The water turns the ground green. I read (on a different post) about putting upside-down carpet in the planter, below the plant to help keep the moisture close to the plant, but I would love any suggestions to prevent any leakage from the pot, recycling the water back into the plant, or keeping the water in the plant in such a way that the roots don't rot, etc. Thanks in advance!

[Kisal]

Welcome to the forum!

If the water doesn't drain out of the pot, the plant's roots will rot. No way to avoid that.

The "green" you see on the concrete is probably algae. It should be easy to kill it with a little algacide, such as is made for fountains, birdbaths, ponds and aquariums. It works really well in my ponds and birdbaths.

I would just put a capful of the algicide in a bucket of water and pour it over the green area. You may need to use more of the algacide and water solution, depending on the size of the area you need to treat. Another method would be to put the solution in a plant sprayer and spray it on the green area. It might be necessary to scrub the dead algae off the concrete after the first treatment, but regular follow-up treatments, maybe once a month or so, should prevent more algae from growing. It's what I would do, anyway.

[rainbowgardener]

The traditional thing is just to put plant saucers under them. The saucers come in all sizes up to very large and have ridges inside to lift the pot up above the water a little bit. Once the water is finished draining in to the saucer you can just dump it. If your pots are too big to lift to drain the saucer, just be careful not to water so much that you fill it.

[Lori Phipps]

Thank you so much. We will also explore the upside-down carpet idea to help absorb the water and keep it near the roots, without rotting them. These are very large pots (tree sized). Someone should invent a system for people who find it necessary to put large pots onto concrete. It would be great to have a solar-powered system where you could fill a separate container through a tube that stores the water in the bottom of the pot, and pump the water to the top each day (The planter would capture the excess water and re-use it). So...all the person would have to do is to refill it as necessary. Oh well. Thanks again!

[rainbowgardener]

There are self watering containers with a reservoir at the bottom. They don't pump the water up, they wick it up.

In the large sizes, they are pretty pricey:

https://www.gardeners.com/Terrazza-Square-Planters/PotsPlanters_SelfWateringPlanters,16028,default,cp.html

One of the thumbnails on that page shows how it works. It would never leak on to your patio.

https://www.bigplanters.com/mm5/merchant.mvc?

gardeners even sells a conversion kit very cheap to convert any container to self-watering.

https://www.gardeners.com/Adjustable-Reservoir/PotsPlanters_SelfWateringPlanters,34-507RS,default,cp.html

[jutsuri]

I just have to mention that watering potted plants with their own runoff isn't very good for the plant, like animals plants have to get rid of waste products and they do it passively by letting it run out with the excess water. Watering with runoff will eventually cause your dirt to smell like sewage because essentially that is what it is, plants have to pee too!

[rainbowgardener]

I don't know that that is (mainly) what you are doing with the self-watering reservoir. You put clean water in the reservoir and it is sucked UP by the wicking. There should not be much reason for excess to be going down into the reservoir.

[jutsuri]

I was referring more to the idea of 'recycling the water back into the plant' brought up in the initial post than self-watering planters. Having said that my mother tried her own form of watering through wicking up the bottom of the pot and ended up with stinky dirt, which is how we learned about the whole idea of plant waste and the need to get rid of it. I remember distinctly the smell of that nasty dirt and I just had to share what I learned, maybe it will save someone else from having to deal with that yuckiness.