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Ericaceous or not

shazza 3shazza 3 Posts: 185
hello. i've recently bought 4 x new Japanese Acers that i am putting in ceramic pots because my soil is not suitable for them. I read that they should be planted in either John Innes No 3 or John Innes Ericaceous. I'm a bit confused because a few years ago i had to rescue a larger version from my son (the plant had been left there by a previous owner) as his puppy decided it would be fun to drag it around the garden and through the house !!!! Thankfully, it has grown into a lovely shrub but i'm not sure if it's in ordinary potting compost or ericaceous as we didn't originally plant it up, however, it's doing great and i topped up the compost last year with ordinary stuff as i didn't know any different. 

Can someone enlighten me as i don't want to cause damage to my new plants ?? Are they sold in ericaceous compost in garden centres ??

many thanks


  • Hello! I always use the RHS website, I looked this up: I hope this is the type of acer you have, if not test out the search box (you might need to look up the Latin first). It says that the soil ph can be neutral or acid. I would probably play it safe and go with a mix of normal compost and ericaceous, or just ericaceous if you only want to buy one type of soil. Remember if you go with ericaceous for any plant, it is best to water them with rain water only as the ph of tap water can change ericaceous soil. Hope this helps :)

  • shazza 3shazza 3 Posts: 185
    Thanks for the reply. I'll have a good look on there before I buy. No good buying wrong compost. 
  • BobTheGardenerBobTheGardener Posts: 11,391
    edited June 2019
    I use three parts JI#3 mixed with one part ericaceous which ensures a slightly acid mix.  Some standard MPCs contain lime so are slightly alkaline and best avoided (as well as not being suitable for long-term plantings, which is why JI#3 is usually recommended for potted trees.)

    A trowel in the hand is worth a thousand lost under a bush.
  • shazza 3shazza 3 Posts: 185
    thanks for that. i have read conflicting information and really wasn't sure which to use at all, that's saved me a lot of angst 
  • shazza 3shazza 3 Posts: 185
    Having re-read the post from Louise, do I still need to use rainwater for these plants ?? Obviously not a problem at the moment !! Thanks
  • BobTheGardenerBobTheGardener Posts: 11,391
    Always try to use rainwater on anything planted in acidic soil if you can although the occasional watering with tapwater won't harm it.   It's important to never let a japanese acer in a pot dry out as they don't like that at all, so better to use tap water than none at all.
    A trowel in the hand is worth a thousand lost under a bush.
  • ObelixxObelixx Posts: 28,840
    I agree and rainfall rarely delivers enough water to a plant in a pot, especially when it has its canopy of foliage, so put them up on bricks of pot feet and water regularly throughout the growing season.  If your tap water is alkaline you can always correct any changes to compost acidity by adding some sequestered iron or feed for erciaceous plants to the can.
    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • raisingirlraisingirl Posts: 6,449
    edited June 2019
    IME acers are lime haters as opposed to acid lovers. Ericaceous compost is safer because you can be sure it doesn't have any lime in it - as BobtheG said, a lot of standard MPC does have lime in it so it's a risk.

    I have two different acers potted in normal (i.e. not ericaceous) JI.3 and topped with bark chips and they are perfectly happy.

    And similarly if you have very hard water in your area, (if you live in a limestone area) then avoid tap water if you can. But if your water is either soft or fairly neutral, use rainwater when you have it and tap water when you don't.
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first” 
  • shazza 3shazza 3 Posts: 185
    Many thanks for all the replies/information. Although rain doesn't penetrate the canopy of larger shrubs, mine are fairly small at the moment and with the amount of rain we've had over the last month, they are not struggling for water !!! However, i will invest in some small water butts although we live in a softwater area (South Wales UK) and the pots are very unlikely to dry out.  
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