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Best way to handle runoff from gritty mix?

Posted by michael_ames 7 (My Page) on
Wed, Feb 27, 13 at 1:55

My office at work has the standard complement of indoor plants - tropicals and ficus - currently planted in tiny pots filled with moisture-retentive potting soil.
We're moving to a new office in a few weeks - one with much more light - and I thought I might as well repot into bigger pots and better soils in the process.

The gritty mix seemed like the best choice to me - almost impossible to overwater and stable for a few years.
But with such a fast-draining soil, how do I handle the runoff from the bottom of the pot?

If I'm watering as I should - not in sips, but infrequent, deep watering - there will be more runoff than even a deep saucer below the pot can handle, right? At home I could probably move the pots to the bathtub and water there. At an office, that isn't an option.

Any suggestion for a setup that helps deal with this issue?
Should I try to find a deep trough to put below the office plants to catch water? Look for saucers that also include a spigot?

Creative ideas welcome.


Follow-Up Postings:

RE: Best way to handle runoff from gritty mix?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Feb 27, 13 at 11:04

You could always do a pot within a pot. you would take a big pot without drainage and place the pot with drainage on a brick inside it.

RE: Best way to handle runoff from gritty mix?

You should be able to find large enough saucers to contain the runoff water, and evaporate before the next watering. It works for me, just be sure the pot is raised above the water level in the saucer. If you use clay saucer, you will need to seal it so it does not seep through and damage the floor. Al

RE: Best way to handle runoff from gritty mix?

  • Posted by rina_ 6a Ont (My Page) on
    Thu, Feb 28, 13 at 14:28

I do same as Al - large saucer and pot sitting on clay 'pot feet'. Works well.

This post was edited by rina_ on Thu, Feb 28, 13 at 14:30

RE: Best way to handle runoff from gritty mix?

Thanks for all your suggestions, everyone.
I definitely see this working for the smaller plants we have in the office - but is a different solution required for small potted trees (like a 4-5' ficus)?

Maybe I'm overestimating the amount of runoff I'll have.

-I've read that the gritty mix retains maybe 10% of the water you use

-I've also read that one should water deeply to heavily saturate the soil

If we're talking about a 5-gallon pot I feel like I'd need quite a large saucer to catch the runoff!
Am I making any faulty assumptions?

I was also thinking about getting something like a deep trough that sit below a large grouping of the plants.
Who knew caring for indoor plants could double as exercises in creative thinking?

RE: Best way to handle runoff from gritty mix?


Thanks for posting that picture, it gave me a good idea. Right now I'm using a very similar glazed clay drip tray, but I just ran 2 2x4's spanning the width of the tray. The pot rests on top of it. It looks hideous though, and I think something like what you've set up will look a lot nicer!

-Mike B

RE: Best way to handle runoff from gritty mix?

  • Posted by rina_ 6a Ont (My Page) on
    Thu, Feb 28, 13 at 20:42

Mike B

I started with 2x4 too, then found these feet (in Restore of all places, for a $1), and grabbed them to use for this purpose.


The plant in my photo is a Ficus Benjamina, and it is 8feet tall. Too large to carry to the sink or shower. The pot is 17"diameter and the saucer is 20"diameter and approx. 1.3/4"deep. I bought the saucer in IKEA (originally planned to use as a bird bath...).
I water ir approx. every 5-6 days - it is in free draining potting mix (known here as 5-1-1) and whenever I water, there is a run-off. Saucer is deep enough to keep water contained.
(Ficus B. used to be in 19" pot, I 'downsized' pot after root pruning last summer). Ficus is growing very well.


This post was edited by rina_ on Thu, Feb 28, 13 at 20:50

RE: Best way to handle runoff from gritty mix?

You old pros correct this newbie if he's wrong........but I believe the ideal watering method is to use enough water so that 15% runs through, right? If you are looking for 90% run-through, that seems like way too much.

It will take a little experimentation to learn how much water to use. Use a measured amount, and in your case eyeball what flows out into the saucer. Work toward 15%, I believe.


RE: Best way to handle runoff from gritty mix?

Hi all -

For my outdoor plants with gritty mix, I water freely so it hasn't been a problem. But for the indoor plants -- to have only 10-15% run off would leave me feeling like not everything in there is wet....and to have more than that, none of the saucers accompanying these pots would hold that much water.

For the small ones, I've been running everything to the kitchen sink and I put my hand over the drain hole to FILL the pot w/ water. I hold it like that for about 20-30 seconds, then release and let drain. I can even do that with most of the 12" or less pots.

But the larger ones present a steeper challenge. Without excessive run-off, I'm not convinced all of the bark and Turface are adequately soaked. With excessive runoff, I'd be living in swamp.

Like Rina's post above -- if I let it drain, then I do have to move the pot. And with gritty mix in a large pot, that is no small feat to lift with one hand to remove the saucer below.

Any ideas -- other than working out to increase arm strength???

RE: Best way to handle runoff from gritty mix?

Without excessive run-off, I'm not convinced all of the bark and Turface are adequately soaked.

In my experience, the gritty mix picks up and holds more water than is immediately obvious. I have a lot of large plants in 5-10 gallon pots of gritty mix, some of which weigh 30 to 40 pounds when well watered, so I need help to lift them. They are all in drainage saucers that are 3-4 inches deep and 4-6 inches wider in diameter than the pots. I water them only about once every two weeks. I start by slowly pouring one to two quarts of plain water in the pot carefully distributed across the surface. About 10 minutes later, I slowly pour in another two to four quarts (depending on the pot size) with full strength foliage pro in it. I watch to see how much water drains into the saucer. I allow as much as two inches to collect in the saucer. Most of the time, the water will be absorbed back into the pot within 10-20 minutes. About once every 6 weeks or so, I water enough to almost fill the saucer. After about 20 minutes, I use turkey baster to remove excess water. Sometimes I get help from my DH to lift the pot out of the saucer long enough to pour excess water into a large pail.

This is obviously not the ideal way to handle watering since the mix is not flushed each time I water. But in the six months my plants must live in a centrally heated house with fairly low light, they grow slowly. But they do grow with this regimen. They don't lose leaves or develop signs of inadequate watering. These compromises work for me. And I think they work for my plants.

When my plants were in a more water retentive mix, I had no problems with excess runoff. My plants in gritty mix are actually getting flushed out more often than they were under my old regimen. And they definitely look better at the end of their six months indoors than the ones I had in peat-based mixes.

RE: Best way to handle runoff from gritty mix?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Mar 7, 13 at 16:35

Even if a well-made gritty mix is totally dry, the Turface soaks up water until it's saturated, and the surface of the grit gets coated with water. Then, water vapor disperses into the dry bark, which 'breaks' any hydrophobic tendencies the bark might have. Ideally, you would be watering before the soil gets that dry, so the bark ISN'T hydrophobic and also absorbs water, but it's not really necessary - you just need to allow for the fact the bark was dry and make sure you account for the fact next time you water ..... or wait a half hour and water again so the bark is sure to absorb water.

If you water slowly and be sure to cover the entire soil surface, you won't have any dry spots and can get away with watering so 10-15% of the total volume of water applied drains into the collection saucer, though 20% would be better. Do be sure to keep your pot's bottom above the level of the effluent in the collection saucer at all times - or there is no gain in flushing the soil.


RE: Best way to handle runoff from gritty mix?

Ohiofem and Al:

Will do that -- water more slowly. To date, I just water enough to completely soak it through, but it results in a far bigger than 20% runoff...probably more like 200%, haha, but at least I know it is soaked through. To date, as most of this is newer, I don't have anything I can't take to the sink just yet, though the rubber plant is bordering on it. So that plant, I have used a double saucer; one is a clay saucer that fits the size of the pot, and another is one of the plastic "saucers", meant for a significantly larger pot. I suspect it can catch at least 100% excess without flowing over to the carpet, even if it's not the prettiest setup in the world.

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