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macfallmacfall Posts: 34
in Plants
I bought some John Innes No.3 compost to put in a pot for a patio rose.
In the base I put some broken terracotta, about 2inches in depth.   I did carefully pile the lumps on top of each other, hoping to provide drainage. I filled the pot nearly to the top and soaked it throughly.  The water did run out but the compost was very wet and has shrunk by half, and is quite stiff.  I am more use to working with bedding compost.
Fortunately I hadn't planted the Rose. Do you think I should have put some smaller lumps in.  I don't want the Rose to rot. 

Posts

  • Pete.8Pete.8 Posts: 11,340
    John Innes is good stuff, but I find it needs a good 20% of horticultural grit added or it just doesn't drain well.
    The other thing the pot will need is pot feet or something similar (I use thin offcuts of wood) to raise it off the ground a bit so that it can drain easily

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • bédébédé Posts: 3,095
    edited October 2022
    One difference between soil-based compost (JI) and general purpose peat-like, is that John Innes needs a bit of firming in; the peaty settles with watering.

    One question is: did you fill the pot and water, before you had planted the rose?  And was the rose bare-root or in peaty compost?  The normal technique is place some compost in the pot,  then position the plant, then top up the pot with compost, making sure there are no air-pockets.  Then water thoroughly.  At this time of the year do nothing more until late spring. 

    If there are lumps in the compost, break them up a bit.
     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."
  • bédébédé Posts: 3,095
    edited October 2022

    All commercial composts are formulated to be used as is.  For a rose I would not add anything extra.  But for some plants, definitely.

    I have found that some peaty composts will compact after a year.  I usually add vermiculite to my composts for hydrangeas.

    I do not use pot feet, and have never had any problem with drainage. Pot base to terrace paving is not an hermectic seal. At least not chez moi.   I have used them to deter ants.  And to restore level on an unlevel surface.
     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."
  • PlantmindedPlantminded Posts: 3,580
    If planting a shrub in a container where it's likely to stay for over a year, I use John Innes No.3 with added multipurpose compost and horticultural grit, in a ratio of approximately 50% JI, 30% MPC and 20% Grit, depending on what leftovers I have!  This seems to improve drainage, while retaining the moisture retaining quality of the JI compost.  I always use pot feet to aid drainage, or a saucer in summer to keep in extra moisture for plants that need it.
    Wirral. Sandy, free draining soil.


  • NollieNollie Posts: 7,529
    For roses, JI3 or equivalent loam-based compost is a really good nutritional base, but on it’s own is far too claggy. Mixes vary but I always mix in around 30% MPC for drainage plus a spadeful of ordinary garden soil and the same of bagged manure for extra oomph. Roses love a rich soil and manure. Personally I don’t bother adding grit since I find if you make it too free-draining all those precious nutrients the rose needs are washed out the bottom.

    As bede says, the usual way of planting anything in a pot is to put some of the mix in the base then fill up around the plant then water. You want the graft of the rose (the knobbly bit) a couple of inches below the soil level and the soil level itself a couple of inches below the rim of the pot so you have room to water, feed and mulch.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • macfallmacfall Posts: 34
    Thanks everybody for your advice, I will take it on board.
  • bédébédé Posts: 3,095
    macfall said:
    Thanks everybody for your advice, I will take it on board.
    Thank YOU.  We don't get many thanks on here.
     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."
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