Roots In Containers & Grow Bags
The first thing a tomato plant needs is a good root system when growing in soil.

The larger the area the roots cover, the more chance a plant has of providing all that is needed.

That’s why it’s a good idea to give roots a little scare when transplanting into a new pot.

Water them well when first transplanting, then give it several days before watering again (keep your eye on them just in case they dry out too quickly).

This makes them grow quickly – after a few days they’ll start to worry – they don’t know when or if they’ll be watered again!

The problem with containers however, is that space is limited, soil nutrients are limited and water runs out quickly which means that roots in containers often have too much water or not enough – moisture levels are up and down like a yoyo, plants become stressed and under-perform.

Tips from hydroponics
Tomato plants that are grown hydroponically have smaller root systems … why?

They have access to the optimum levels of water and nutrients 24/7 so they just don’t need a large root system.

So, as soil growers, what can we learn from these (spoilt!) plants?

The thing is, they produce the same results (often better) but with less root area, so if we could reduce the pot/container size required for final position plants, we could cut down on the amount of potting/grow bag compost we use and have more room to grow more plants!

It’s all about the “Two A’s” … Air and Access

  1. That’s air in the soil
  2. Constant access to nutrients and water whenever the plants need them.

The air part of this is easy to accomplish by adding perlite and using an air/fabric pot or air pipe.

Large pot, wick and air pipe.
Large pot, wick and air pipe.

For roots to have access to water and food around the clock is another matter.

If roots are stood in a tray of water 24/7 and soil becomes saturated, they will almost certainly develop problems, the only sign of which will be a poor yield and another disappointing season.

Smart valves and Aqua valves can overcome this problem by creating a wet/dry cycle.
The aqua valve is used as part of the “Autopot System”. It’s a great way to grow tomatoes and peppers etc., but is a bit expensive to get started.

A more simple way to achieve a regular water/nutrient supply is by using a wick system and capillary matting.

Large Pots

  • Stand a large pot on a tray of perlite or gravel.
  • A grow bag tray is good for this purpose.
  • The tray is filled to the brim with perlite/gravel then water containing food.
  • Cover the tray with black plastic to stop light which encourages algae.
Capillary Matting for Grow Bags
Wick method for grow bags & pots.

Grow Bags

A grow bag can be optimised in the same way.

  • Cut slits in the bottom of the grow bag.
  • Lay it on a sheet of capillary matting.
  • Have a wick of capillary matting from a large container of water to the sheet under the grow bag.

The wick system is also used in the “Quadgrow Planter” which gives very good results too.

Another advantage of this method of watering and feeding plants is you won’t have to worry if you are away for a few days.

I’m off to the polytunnel to pot up some Red Alerts … have a good weekend!