'Stunted' pot plants cannot reach full potential

[Colin Miles]

Now here's a really interesting bit of news!

http://www.bbc.co.uk/nature/18612661

Glad I chose the larger roottrainers.

I wonder if it applies to patio potatoes?

[solway cropper]

It's amazing what 'research' can come up with. I think gardeners have known for an awful long time that pot-bound plants don't achieve their full potential. Isn't that why we pot them on?

I currently have container grown peas which are twice the height it said on the packet and Rooster potatoes with foliage up to chest height.

In the UK the only thing that stops plants reaching their potential is the bl**dy weather.

[Colin Miles]

Hi SC - if you read the article carefully I think you will find that it is not just a question of a plant being pot-bound. It could suggest that the initial size of the pot will also influence growth - hence my comments about the size of roottrainers.

Also I noted the comment

Plants grown in pots that are too large are susceptible to root disease because of excess moisture retained in the soil

May sound obvious, or not. But it brings me back to another comment about the problem of watering containers/pots.

[Johnboy]

Hi Colin,
The size of pot used can very seriously affect the progress of the plant.
For instance taking cuttings of shrubs stage one into modules stage two into 8cm round terracotta pots. If at stage two you chose a 1 litre pot the cutting would not flourish but takes a serious check in growth but if you go from 8mm pot and then pot on to a 1 litre the plant will flourish yet you might think that the reverse would be the better practice.
JB.

[Colin Miles]

Hi Johnboy,

Thanks for the response but didn't quite follow the stages. 1 is? then 2? then or?

[peter]

"8mm", seriously an eight millimetre diameter pot?

[Johnboy]

Hi Peter,
Should have read centimetre. Have amended posting.
JB.

[Geoff]

It seems to suggest that the optimum timing of potting on is a bit different to accepted practice. Usually you pot on when the pot is reasonably full of roots but it looks like it would be better done as soon as the roots reach the bottom/outside of the pot. Probably coincidence but this year I have grown some good perennial flower plants from seed. They have been potted on earlier than sometimes because I have been looking for jobs to do in the dry rather than them having to wait until a bad day or I think I can't leave them any longer.
The Rootrainer situation is interesting. The advice is usually to air prune the roots by letting them get quite pot bound before planting out. The tall ones do take quite a lot of compost though I haven't measured the pot size equivalence. I have sometimes had the feeling plants establish better if you manage to time planting out to when the tubes are just full, difficult to judge as there are so many factors at this stage like the state of the ground they are going into and the weather.
Another factor is when you are growing a plant for flower then fruit size isn't everything. A bit of stress often encourages an earlier crop.

[Johnboy]

Hi Geoff,
Cuttings here were initially struck in 1.5"x1.5"x2" module trays of 126's and when they have rooted and have a root show from the base of the module are then potted on into 8cm pots until the same occurs in the 8cm pots which, with vibrant cuttings, doesn't take that long. They are then potted on into 1 litre pots and from there planted out either into the nursery row or potted on into 1.5L or 2L pots. It all depends on the plant involved and at what size you intend to sell it.
If you are taking cuttings for your own use then using larger pots is the preferred method.
JB.