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Crocks in plastic pots

I always put some crocks in the bottom of my terracotta pots. I have just purchased some 20l plastic pots with 12 pre-drilled drainage holes. (Large version of indoor pots). Do I need to cover all of the drainage holes (a lot of crock), as you don't cover holes in houseplants? 


  • FairygirlFairygirl west central ScotlandPosts: 35,372
    The reason for covering holes is to prevent the soil dropping down when watered, and blocking the holes completely, so if you're planting something to leave outside, it can easily happen, and isn't great for anything which needs decent drainage.
    You could use a layer of cardboard or landscape fabric with just a couple of crocks to lift it a bit, and that should help. I often do something similar if it's a pot with multiple holes. 
    Unless I'm misunderstanding your query.  :)
    It's a place where beautiful isn't enough of a word....

  • The idea of landscape fabric is great. I have some weed-suppressing membrane which would probably solve the problem. Many thanks. 
  • FairygirlFairygirl west central ScotlandPosts: 35,372
    I find it works well, although just watch for roots sticking to it a bit.  ;)
    It's a place where beautiful isn't enough of a word....

  • Blue OnionBlue Onion Posts: 2,500
    I use weed suppressant fabric as well.. or even just a paper towel.  By the time the paper towel rots away, the soil has settled and doesn't drain out or cause an issue.  

    Crocks in the bottom have been disproven -

    “But a study by consumer magazine Which? suggests it's a myth. Researchers planted 40 pots each with five "Million bells trailing yellow" - a flowering plant prone to root rot in saturated soils. Permutations involved plastic pot, and terracotta pot, and with either saucers or no saucers. Half got crocks, half did not. The plants were recorded for "vigour and flowering impact". The magazine found that the crocks "made no difference to how well our plants did".”
    Utah, USA.
  • FairygirlFairygirl west central ScotlandPosts: 35,372
    I still like to cover the holes, in a way that allows water through, but not clogging, especially if it's a pot with only one hole.
    We have a lot wet here, so I feel it helps, especially for anything in a pot long term, or for bulbs.  :)
    I do still use the alternative i mentioned though, as it's a good method too. Another one I use is the bottom of old plastic pots that have split, or those containers meat and fruit etc come in. It helps 'stagger' everything, if that makes sense  :)
    It's a place where beautiful isn't enough of a word....

  • Weed membrane or carboard/paper it is simply to stop the compost falling thru the holes until the roots take over.
    Depends what you are planting of course as to whether you may also need a layer of coarse grit at the base.
    Whichever way you choose , you will still need to ensure the pot can drain any excess water whether a house plant or outside plant. 
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