Read at :

The Vegetable Grower

http://www.vegetable-garden-guide.com/The_Vegetable_Grower-the-vegetable-grower-july07.html

Containers are Thirsty

Even though I have a number of raised beds I still like to grow veg in containers. Why? Because there is always some little area somewhere in the garden that I can slip a container or two into and capitalise on the `wasted` space. But this time of year be careful to check on your containers often as they can dry out very, very quickly - those plants are very thirsty in sunny weather.  It may be that you need to water a couple of times a day in hot weather. I had a largish container with four climbing French Beans in last year and boy were they thirsty and watering twice a day was the norm in hot weather - they have masses of fine rots which filled the container in no time. If you see the compost shrinking away from the sides then it is becoming too dry and you may need to soak the container in a bucket (or some such water holding container) for a couple of hours to re-soak the drying compost. If it is too dry it becomes `waterproof` and any water being poured on will mostly run down the gap between the compost and container side. 

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MY COMMENT

Containers drying quickly is one of the common problems for container gardeners. I am happy to tell you that I have excellent results when mixing the potting soil with a soil conditioner like TerraCottem (see http://www.terracottem.com).  It is mixture of some 20 different substances, on the basis of water absorbing polymers.

We all know the problems with dried “organic” potting soil or compost, becoming even waterproof.  Well, I am using all kinds of containers, preferably PET bottles and plastic shopping bags (as grow bags).  I am filling them with a classical “universal” potting soil, containing a lot of organic matter, to which I add 5 g of TerraCottem per liter of soil.  At the start, I am watering to saturation, in order to get the water stocking polymers swollen to  maximum.

There is less evaporation in the bottles and bags.  The rootlets are sticking themselves to the swollen hydrogels and are even penetrating them (all kinds of nutrients are also absorbed by these gels).  The potting soil is shrinking less.  Of course, there is always the transpiration of the plants, so that I have to water from time to time, but certainly not every day, even in the hottest periods.

Let me recommend container gardeners to give it a try.  And even if you don’t have the TerraCottem soil conditioner in your area, set up an experiment with water stocking polymers to be mixed with your potting soil.  Success !