Why are big pots bad for small plants?
I've googled this and it says that the soil will be too wet. I don't really understand because people plant things straight out into the garden, which is bigger than any pot.
I don't like the thought of regularly repotting and disturbing the plant. Is that not bad for it too?
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When placed in oversized pots, small plants can expend all their energy extending their root system and not enough on creating foliage and flowers, so all the work goes on below the soil. It sounds a bit counter-intuitive, but true to say that plants can tend to have their growth stunted by being in too big a pot. Much better to provide limited space for root growth initially so that the above-soil part of the plant develops and then re-pot it before it becomes pot bound.
Last edited: 08 September 2017 14:26:04
Garden soil is a bit different. It's free draining and well oxygenated, and full of microbes and worms. Potting compost in a large pot can go sour if it stays sodden too long. Also, it's a bit wasteful to over-pot things, and looks a bit odd.
Small plants put into the ground don't necessarily grow well compared with plants which are filling a bigger pot. It will depend on the plant and the time of year etc. Planting out little plants in summer can often be better than them sitting in a big pot of sodden compost, as already mentioned. It's sometimes a judgement call, and that comes with experience of your location and soil conditions
For instance - I have a few small geraniums grown from seed. They're in 3 inch pots just now and filling them well. I could plant those out in summer when the ground (in theory!) is favourable, and the weather is kinder. I'd even consider planting them now, although it's much colder than ideal, as they're well grown and filling the pots, and they're hardy.
Those same plants put out in December,January or February would sit in cold, sodden ground and would struggle to survive and thrive.
I live in west central Scotland - not where that photo is...
It does depend on plants. You don't mention which plants you have in mind. I have different size pots but will not think twice about putting something small in a pot that is too big. More often than not the plant will grow big. In fact it's the opposite, always underestimating a plant's growth.
I don't think there is any issue planting small things into a large pot, it's all about choice and style, but keep the base part of the pots full of grit or large stones. Drainage is something you may need to think about for small shallow roots that may get clogged in rich soil.
Thank you for the replies. It's for my new Holly bush. It's only very small at the minute.
Would putting a smaller pot inside the big pot be ok? Or adding lots of perlite to help it drain?
If it's very young then you can do that. If it's already 20cm in height, I think the shrub can deal with it quite well. I would even suggest you pot it into a loam based compost if it's beyond 20cm in height.
Potting on is as much about providing new soil/ compost to keep a fast developing plant well fed & growing strongly. If this is an annual early in the season you do this to "keep it moving on " as the experts would say. This is also about balance you do not want it to sit there making lots of root as you want it to grow & flower & give you a display when you do put it out. With a (relatively) slower growing perennial such as your Holly you sill want balance between roots & top growth. Overpotting as others have said can lead to roots rotting in stagnant soil at the bottom of the pot. You can put a smaller pot into a larger one for display purposes this is often recommended for young Acer trees.
If I add other plants along with it, is that better? I have 3 lavenders and I could put them in the big pot with the Holly. I think they both like well drained soil. Would they be ok together? The lavender isn't doing very well so far though. I'm not sure if it's really alive. Here's a pic of them.
I don't recommend you grow them with Lavenders. The Lavenders will not require much watering whilst your Holly will need it quite regularly. The other issue is Lavenders will also dwarf your Holly which is not the ideal condition for your young shrub. This may cause rotting and encourage fungal growth.
When you have a young plant like Holly, I don't recommend you plant anything too near it. They need time to establish and grow. Your Lavender looks quite poorly. Probably needs to be dug out and put somewhere that is not full of grass around its base. This damp condition will cause the base area to rot. I do think they may benefit being potted up with gritty soil. That allows them time to have more drier conditions.