Topping up large container

Hi all,

I have a very large container into which I have a bamboo planted but the level of the soil has now dropped down quite low. Do I need to dig out the bamboo in order to top up or have I just remove the stones and add some MPC on top?

Many thanks!

 

Hello @latimer good to see you here! You could take a chance and just top the bed up but if your bamboo is going to be in the container long term, I would remove it and refresh the compost completely, using a soil based compost like John Innes No 3. I have found that after a couple of years most bamboos become weary in containers. Ideally it would be better off in the ground, if you have space, with a suitable barrier installed if yours is a running bamboo.

 

Hi @Plantminded, likewise!

So the container was filled with a mix of topsoil and MPC, not just MPC but the level has dropped considerably nonetheless. I'm tempted to persevere with it in the container as I don't know another suitable spot in the garden for it at the moment. However, I think I will dig it out and topped up with a JI3 based MPC.

 

A soil based JI3 will be fine @latimer. You could also add a few handfuls of Blood Fish and Bone on top, before replacing the slate, to encourage new canes which should be appearing shortly. I also like to trim the leaves off the lower third of the canes to show the colour off. See what you think:

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The Multi purpose is the big culprit in pot levels sinking IMO.
Organic matter disappears after a while, soil doesn't.

 

I agree @pete, I've just altered my reply to reflect my earlier post!

 

Thanks @pete and @Plantminded

@Plantminded I like the bamboo with the lower leaves trimmed, I may give that a try!

So a follow up question as I've always struggled to understand this: soil on it's own contains few nutrients, right? So you need some organic matter to feed the plants? So containers will always have this issue of not being permanent and at some point you do need to heave everything out, refresh the soil and replant? I'm asking this as another large container that has ferns and grasses in it also probably needs a top up, will I need to dig everything out to do that?

 

Sorry @Plantminded , I was just adding my bit, not wanting to contradict you in any way.

@latimer , maybe just go for a JI compost, if its claggy I prefer to add sand or grit rather than organic matter in long term containers as its less likely to disappear.
Ji no 3 has the highest amount of fertiliser.

 

@Plantminded probably knows more about Bamboo than I do, I was just referring to containers in general.

 

And then in the future you just add fertiliser such as BFB @pete?

 

No worries, my follow up question was supposed to be general

 

You'll only need to take the plant out if the compost/soil has sunk @latimer, but most plants in containers will eventually become pot bound. You'll then need to repot in a larger container or prune the roots. Most plants in containers will need supplementary feeding as MPC/soil based composts contain nutrients for an average of 6 weeks' growth. There are also some plants like Lavender that prefer impoverished soil and should not be given extra feed. Grasses can also become a bit lax if given too much feed. If you're worried about your plants in containers, post some photos here for specific advice, as there are many variables to consider!

 

Thanks @Plantminded I'll take some pictures when I get back home

 

Or liquid feeding, which I like as its faster reacting.

 

For large containers I often find in the short term a top-up around the planting(s) will hold the situation until I can do as advised. Rightly or wrongly I use JI base mixed with something like MPC. I add a good amount of perlite to the mix for most plants.