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I have a new opening in a pot without drainage where my spider plant resides, which I've decided to move to a more suitable pot for it.

I'd like not to leave the old pot empty, but also not to have to drill holes in it because I don't know if it would break.

Are there any plants that will thrive in a deep pot (about 20cm) that has no drainage?

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    If it's a ceramic pot, you can drill holes in it using either a tile drill bit or a masonry bit without hammer action. Go slow and keep the cut wet. – Chris H Feb 13 '17 at 15:07
  • It seems like a weird polymer rather than ceramic. It is partially permeable and smooth to touch. Strangely it also gets eroded by the salts found in my cactus potting mix, probably because of a chemical reaction between the two compounds. – Gabriele Cirulli Feb 13 '17 at 16:53
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    Strange. Personally I'd either use it as an outer pot as others have suggested, or use a sharp HSS bit with next to no pressure in my wheel brace (hand drill). This is an extremely gentle way to drill. – Chris H Feb 13 '17 at 16:55
  • I would NEVER use a pot without holes. Using pots means an artificial environment and no matter the plant a pot needs holes for drainage. Not to mention sterilized potting soil. No rock or gravel below the soil, the bottom of the pot lifted up off the surface it sits upon. I'd use your pot as a PROP to raise it to another level! Plant is able to get more light usually and makes more interest to a grouping. Tall thin pots are especially dangerous to plant. Too much soil downwards for any plant. Most roots are within 4 to 6" from the surface. Cactus and succulents need shallow pots! – stormy Feb 14 '17 at 19:15
  • @stormy how shallow? I have used normal-shaped ceramic pots for all my succulents so far, usually as tall as the plant itself. Can that actually become an issue for the plant, or is it just that shallower pots provide a more ideal environment? – Gabriele Cirulli Feb 14 '17 at 19:37
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No, is the short answer. Whilst some plants will grow in waterlogged soil quite happily in open ground, such as in a bog garden, soil in a non draining or waterlogged pot can become hypoxic/anoxic and generally 'sour' because of problems with gas exchange, which means plants will not survive, or at least not do well.

With the type of pot you're describing, they're usually intended to be used as an outer container for an ordinary pot with drainage, so if you want to use it, find a flower pot of the right shape and depth to fit inside, plant into that, and remember to empty the outer pot 30 minutes after watering whatever plant you've used.

  • Is it necessary to empty the outer pot whatever the plant? For example I have a papyrus which is planted in a clay pot with drainage holes, itself in a plastic outer pot (without holes). I always leave some water in the outer pot. That way, even if I forget my plant for a while, it can still get water by capillarity through the draining holes (or even through the clay pot maybe). Is it a bad way to go? – Augustin Feb 13 '17 at 20:50
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    Generally, its not a good idea to leave water in an outer pot 30 minutes after watering, unless you know the plant is very dry and having trouble soaking up the water. However, if you mean Cyperus papyrus when you say papyrus plant, that's a semi aquatic, and should be fine with what you're doing. – Bamboo Feb 13 '17 at 21:48
  • Yes I wouldn't do that with other plants. I'm used to call it papyrus but actually it is a Cyperus Alternifolius. I like this plant because it's easy-care, fast growing, and easy to propagate. – Augustin Feb 13 '17 at 22:06
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Typically a non-draining pot is used for growing succulents (especially cactus.) The idea is to water infrequently (once a month or longer) and completely soak the soil. This mimics the natural environment of many cactus species where rains are infrequent but torrential. You cannot water frequently because the plant will die. Also, The bottom of the pot should be filled with gravel and/or sand to leave room for a little drainage.

  • I'm glad that you brought up the succulents since I have 12 glass recipients with no draining holes and they are doing fine for the last year or so. I have to add that soaking is the way to go only if the water will evaporate fast, but if not it's best to avoid it and to add a moderate quantity of water, infrequently of course. – Alina Feb 13 '17 at 15:47
  • Some of my succulents are also in closed pots. What I do to water them is take a small glass, fill it to match about half the volume of the pot itself, then pour that into the plant's pot. It has worked fairly well so far, I haven't seen my succulents suffering from it. – Gabriele Cirulli Feb 13 '17 at 16:25
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    Generally I would fill up the pot with water until it's above the soil and let it settle in. Soaking implies to me actually taking the pot and submerging it in water which is not something I would do with a succulent. Their roots are shallow and the leaves tend to float. Also since dry soil does not readily absorb water, in 15 minutes or so, there should not be any standing water in the pot. If you are watering infrequently, the succulent will be a little shriveled-up and will quickly absorb much of the water. – JimmyJames Feb 13 '17 at 16:41
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Plants are living things and therefore all the cells must breathe. This includes the roots. Even plants which appear to be growing in nothing but water are in fact breathing through the roots, exchanging gases with what is dissolved in the water. As those gases are consumed, the plant eventually has nothing to breathe.

In an aquarium, the plants would soon cease to function if the bubbling air supply was cut off. Plants like watercress can only survive with a constant supply of nutrient rich water that has dissolved gases. Solve the gases problem (with an air pump or mechanical windmill) and you can grow many plants accustomed to being underwater.

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