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Hard crust on peat free compost

Moobloon65Moobloon65 Posts: 3
in Problem solving
Hi all
I love working in my greenhouse and growing from seed gives me tremendous satisfaction.
Last year I had problems with peat free compost drying out quickly - but I solved that problem by sowing in terracotta pots resting on gravel in trays of water. 
This year, (and last), my ongoing big problem is the "crust" that seems to develop on all of my containers with peat free compost in. Sometimes so solid that water runs off it! Any suggestions of brands or mix combinations that will resolve this please?
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Posts

  • wild edgeswild edges Posts: 10,497
    It can help to have a plant sprayer handy and just mist the top of the soil a couple of minutes before watering. It also helps to fluff up the soil now and then. I've use a pump up sprayer and an old kitchen fork. For long term plants I just add a mulch of gravel on top or a thin layer of John Innes.
    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • bédébédé Posts: 3,095
    edited May 2023
    I have had a similar problem with my potted on hydrangea cuttings. The peaty compost consolidated too much.  About1/4 to 1/3 of vermiculite has kept my composts open.

    Coir is notorious fro not rewetting when it dries out.  The water runs off or escapes down the sides, or even straight through, without wetting the compost. 1. avoid coir-based compost. 2. add a small amout of wetting agent (soap or dishwasher liquid).  If you buy into the wild edge mist idea, add the wetting agent to that.

    Look for several recent "peat-free" and "coir" threads.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • rowlandscastle444rowlandscastle444 Posts: 2,612
    wild edges said:
    For long term plants I just add a mulch of gravel on top or a thin layer of John Innes.
    Horticultural grit!! I get through lots of it. 
  • EscapetothegardenEscapetothegarden Posts: 188
    This has happened to me in some of the compost I used to sow seeds.  I was wondering if it could affect them piercing through the top! The water would sit on top and take a while to pass through.  I sometimes even had to give the pot a gentle squeeze.

    :(
  • Moobloon65Moobloon65 Posts: 3
    Apologies for my delay on responding to your comments and kind advice. People stuff keeps getting in the way of my gardening!
    Thanks to all who have responded. In particular I didn't know that coir doesn't retain water (although, when you think about its job when on a coconut .........)!
    Most of my plants have been strong / determined enough to break through from seed but I have had to increase watering frequencies.
    Best wishes with this one - I think it is going to be an ongoing issue.
  • bédébédé Posts: 3,095
    Moobloon65 said:
     I think it is going to be an ongoing issue.
    Too true.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • AuntyRachAuntyRach Posts: 5,291
    edited June 2023
    I’ve had the same on some of my pots. I have taken to mixing the shop bought compost with some of mine. My pelargoniums aren’t as good this year and some of veg failed - not sure if coincidence with the peat free 🤔 
    My garden and I live in South Wales. 
  • EmptyheadtimeEmptyheadtime Posts: 366
    I have been getting this 'crust' too. The dry crust lead me to think the pots/seed trays were dry so I would water them. Trouble is, below this crust the soil was still wet, leading to me over watering some and losing a few small/young plants and non germination of some seeds too. I have been trying various mixes/brands and found my old favourite, jacks magic, to be the worst culprit so far,  so I have switched to another multi purpose for now. 
    Also, I have been getting a fair few weed seedlings in my pots this year, more than normal, so not sure if this is due to the compost too.
  • bédébédé Posts: 3,095
    This is the latest thread on the general subject of composts that i could find.  

    My view and general concensus too is that home made compost will become  important for future gardening.  The big problem is weed seeds and bugs.  Disinfecting above 60ºC is an option, but not easy.

    I have recently come across google links to Hydrogen Peroxide in gardening.  It could be an answer.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • JennyJJennyJ Posts: 10,576
    Can you microwave compost to sterilise it? I have an old one in the garage that I use occasionally for non-food purposes eg dye so I wouldn't be too bothered if it got mucky.
    Doncaster, South Yorkshire. Soil type: sandy, well-drained
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