Establishing young plants 10/03/09

These are some of the young plants i will be growing, sweet peppers on the right, tomatoes in the middle and chillies to the right. There are also some plants called Pepino at the far right which are nicknamed melon pears because of their sweet soft fleshed fruits.
The plants have recently been inserted into the larger 4" rockwool blocks and have been kept under a gentle fluorescent light to let them develop their root system before intensifying the light, i'm using a T5 high output 8-way flourescent light because it produces lots of lightat a low temperature with low power comsumption and has a good spectrum of light for vegatative growth and i can choose between 4 and 8 lights. I'm keeping humidity high into the 70%'s to slow the transpiration rate. I use 2 HR50's for the whole greenhouse which is 75m2, they're linked up to a humidistat to control humidity.

As you can see the plants are sat on mesh grid this allows air to the underneath of the blocks. When roots reach the bottom and come into contact with the air the tip dies back.
Using the analogy of 'topping' a plant where you nip the growing tip off a plant to encourage side branch growth by changing the position of growth hormones in the plant. The same principles can be applied to the roots.

This technique is called air pruning and is something i will always do to get my plants established well enough to cope with environmental changes. Changes from the propagation stage to final planting position include greater light intensity, heat, air movement and amount of water recieved by the plant. Moving a plant too early will put too great a demand on it before it has developed and will stress it to the point of stunted growth, poor root development and risk of becoming disease infected. A well established plant will grow quicker and healthier and have potential to yield greater than one that isn't.

Note: All plant species and varieties among species have widely different root systems some thin some thick, some are abundant others are not.

A technique in commercial grows is to use a root-stock plant and to graft a favoured top part of a plant onto it. This means you use a variety of plant that has been bred to produce alot of roots and is disease resistant. That plant hasn't been bred for flavour or yield so to get the best of both worlds, they simply cut the top off and replace it with a plant that has been bred for flavour and yield. It's a technique i've not tried but am very interested in the benefits as you can choose the best phenotypic characteristic from two plants.