Potting up theory - why in stages? How does a large pot stress a plant?

[Russel Sprout]

Hello everyone

I've been thinking about this with regards my tomatoes, but I'm also curious about it from a more general point of view... I should add that I am a newbie too, with an enquiring mind!

What I'm wondering is, why do plants need to be potted up in stages? Taking tomatoes as an example, why pot them up from trays, on to 7cm/9cm pots, then to 9cm/12cm pots, and then onto their final growing positions? I am presuming that potting them into too large a pot from the start will stress the plant, but how and why?

Yours curiously

Max

[Baldy]

Probably easier to maintain the root ball and judge whether the plant/compost has enough water. A small plant in a big pot might have a fairly dry rootball in the centre, whilst the outer bits of compost/soil are wetter.

For me its sometime a matter of space too - I can't pot everything up into large pots at the same time cos I've only got so much shelving.

Having said that I sometimes just go from small pot to big - all depends...

[vixylix]

Water can go stagnant in the compost because roots aren't using it

[bario1]

Moving 30 whopping great plant pots to and from the greenhouse all Spring would wreck my back.

[Russel Sprout]

Thanks for the helpful replies...

bario1 - I was talking in the example about skipping a 7/9cm pot and going straight to a 9cm/12cm pot. So nothing too back breaking! Don't forget to lift from the knees...

[Thelma Sanders]

I must admit I sow in seed trays, then move to modules, then pot up to 9cm pots. From there they go into final size pots or into the ground/greenhouse border.
Done this way they're 'fed' new compost at regular intervals, which the roots grow out into. If they are put into a much bigger pot the roots make a dash for the outside of the pot (where they prefer to be) without using the feed in the nearest compost. That's how it was explained to me, anyway!

[Cadalot]

As Thelma says with the addition that the with each re potting you can bury some stem that have little hairs on and they will become roots as well so you end up with a tom with a great depth of root system when it goes into the final resting place.

[Bigmallly]

Someone else also want to know the answer:

Potting up theory - why in stages? How does a large pot stress a plant? - gardening forum | gardenersworld.com

[Russel Sprout]

Someone else also want to know the answer

How bizarre! His name is Max as well....

[veggiechicken]

Pity he didn't post his question here as he'd get lots more replies

[Thelma Sanders]

I'd like to know why you really can ignore most of the results from any Gurgle search using the word 'pot'

Are there really more people in the world who are looking for something 'different' to grow than there are ordinary gardeners. ( I'm not suggesting that gardeners can't also be the other sort of person but YKWIM )

[Russel Sprout]

Best I don't write anything about the weed I just found in my garden then

Or the grass for that matter....

Maybe the "other sort of people" were gardeners in a previous life?

[The poly tunnel poet]

As I have a limited growing area, I start in a tray and then on to modules and into the increasing sizes of pots to a grow bag.

I start with fifty seeds,
and move on thirty seedlings,
and pot on fifteen small plants
and pot on nine
to grow six plants.
each time I choose the strongest candidates.
A thick stem carries more water and nutrients with less stress,
than an etiolated sun hunting plant.
I have been led to believe it saves waste as some plants die or weaken at various stages of development, so it saves on compost, space etc....

[Nicos]

Interestingly some plants actually thrive when potbound....

[DannyK]

I'd like to know why you really can ignore most of the results from any Gurgle search using the word 'pot'

Are there really more people in the world who are looking for something 'different' to grow than there are ordinary gardeners. ( I'm not suggesting that gardeners can't also be the other sort of person but YKWIM )

Possibly the same reason as I ignored results from US based engines like Yahoo when looking for butts!