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Clay soil in planters

wesley.mcdermottwesley.mcdermott Posts: 2
in Garden design
Hello, 

We're in the finishing stages of having our garden landscaped and this includes some large white rendered block planters on the edge of the patio. The builders have partially filled them with clay soil and rubble (taken from excavation work in our new build garden), leaving around 30cm to the top of the planter. My question is, would this need to be taken out and filled with something else? If so, what would that be? We plan on planting various Meditteranean plants/herbs. The full height of the planters is 3ft.

Posts

  • coccinellacoccinella Posts: 1,428
    If you intend to use the planters for Mediterranean plants and herbs you don't need to change it. Top with any compost with a little perlite, the planters are tall enough for the water to drain. Assuming there's drainage holes at the bottom of the planter, or no base at all,  you can also use them for bigger plants using the appropriate compost for what you want to grow. 

    Luxembourg
  • FairygirlFairygirl Posts: 55,117
    A foot [30cm] of a good free draining mix should do the job well, as @coccinella describes. You can mix some soil with the compost too if you want - that's available in GCs/DIY stores etc, which will be longer lasting than compost alone, without adding too much nutrition, but anything will do as long as the drainage is good. That would be the main problem if you're in a colder, wetter area, as winter conditions can be more difficult regardless of what you do, but you'd have to just experiment and adapt as you go along.

    The more plants you have, the more moisture they'll take up, but only if they're evergreen, woodier types. You can always add a couple of other plants too, to help with that, if the containers are big enough in length and width   :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • wesley.mcdermottwesley.mcdermott Posts: 2
    edited July 2023
    Thank you @coccinella @Fairygirl - builders will take some of the rubbish stuff out, and top it up with good topsoil. I'll mix it with some perlite and compost as suggested too. :)

    The garden is south-facing and the planters are in full sun. Any ideas on what to put in them would be much appreciated. We're looking for some screening, as well as fragrant and aesthetically pleasing. I was thinking lavender for the most part. Planters are 9 metres long.


  • FairygirlFairygirl Posts: 55,117
    edited July 2023
    The key thing is drainage for the sort of plants you want to grow, so plenty of grit or similar, mixed through it all to help with that. Depending on just how heavy and solid the clay at the bottom is, it can also be worth putting a layer or two of chicken wire over that before adding the  new soil mix, as it will help prevent the new mix falling through over time. 
    The drainage holes are very important, so just makes sure they won't get blocked up. If the planters are directly on the ground, it should be ok, but it's worth having some weep holes with some mesh, or similar, over them so that soil doesn't clog them up. Again, that's more necessary in very wet areas.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
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