Kia ora Jani
I have success in growing all sorts of trees and shrubs in pots for the last 6 years now.
And almost all of my pot plants are productive.
The usually problems with trees in pots for a long time are:
* The roots grow get so excessive that the tree suffer from it. The tree root system virtually start to strangle itself in the restricted space.
You have 3 options.
- Do nothing. The tree will get weak and very slow growing after a while and it will unlikely start to fruit.
- Cut the root system back (at the right time of the year) when it has filled up the pot.
This is A. time and labour intense (every year again, forever) and B. risky in damage the tree in the process or catch a disease at the
open cutting wounds.
- Put the tree as young as possible in a root control bag and the root control bag in a pot with about 10 cm space (around and on the
bottom) between the bag and pot walls. This non-woven (needle punched) bags out of geo-textile encourage the roots to grow through
the bag fabric. The magic of the root control bags is that the roots can't widen the hole where there growing through.
The hole will stay about max. 1mm wide no matter how much force the tree roots apply to widen the hole.
This makes the tree "think": "OK, I'm done with root development. Let's stop growing and spend energy in fruiting."
The brand I have good experience with is the "Smart Pot":
http://treebag.com/root-control-bag/ You can get them worldwide for
example from:
http://www.horticulturesource.com/high-caliper-3-gallon-smart-pot-10-x-8-5--p20408/ 3 gallon bags in 42 litre pots produces 1.5m to 2m
productive trees in my setup.
*
Perfect watering of a tree in a pot can be a challenging task because of the little volume of buffering soil.
My solution to this problem is using a true on-demand fully automatic (power-free) irrigation system.
The best systems that I found (after testing a lot of them) are the two systems from
http://www.blumat.com/en/ The dripping system need a little pressure. About 0.25 to 0.5 bar. But it is really good in perfect adjusting (with some patience...)
the irrigation cycle (deep and length) to the total satisfaction of your tree specimen.
I improved the water distribution of the Blumat dripping system with connecting a cycle of a 4/8mm porous irrigation tube with a
T-connector at the end of the dripping tube. You get a total even water distribution this way.
* Fertilizing
You HAVE TO fertilize your trees in pots. The soil volume is not enough to feed productive plants.
You want an *organic* full spectrum fertilizer. I recommend you this two:
General Hydroponics BioSevia GROW and General Hydroponics BioSevia BLOOM
For example from here:
www.servovendi.com/uk/catalogsearch/result/?q=BioSevia (they send international for a good price)
2 ml per 10 litre irrigation water of the "Grow" one in beginning of the growing season. Changing to 2 ml per 10 l "Bloom" when the
plant starts flower/fruit. Raise the dosage when the species can deal with it.
(I can't find any good organic
slow (3-6 month)
release full spectrum fertilizer at all)
Good luck
Andy