Re: [tomato] Tomato Digest V1 #404

Richard Yarnell (
Sat, 29 Jul 2000 22:12:43 -0700 (PDT)

That's only about 5/100ths of a gallon, barely enough to wet the surface.
The water, a great deal of it, probably evaporates from the surface or is
taken up by shallow roots before it penetrates.  

Try putting 90 minutes of that drip rate into the pots once a day until
you see water coming out of the bottom of the pot.  It may take some time
to get this to happen.  Then calculate how much water it would take to
make a 1" puddle in the diameter of the pot.  Run your emitters long
enough twice a week to produce that 1" depth.  (Normally, once a week,
depending on weather conditions, would be enough, but the entire root ball
will be at a higher temperature in the pot than it would be in the ground.

If the plants wilt, apply the full amount of water you've calculated each
and every time.  It will take a little while for the roots to fill the
pot.  Drought resistance is dependent on a deep root system.

I'm sure the 10 minutes came from the example in the timer instructions.
In my view, that contradicts one advantage of a drip system: deep
irrigation with a minimum of evaporative loss.

On Sat, 29 Jul 2000, Bob Addison wrote:

> First time corresponding,  been subscribing since about #350.
> Live in Twin Cities, MN 
> Growing tomatoes in pots, 15" dia. and 15" tall sitting on a concrete
> slab (base for a screenhouse that blew away)  maintains heat during 
> the night.  Growing six different varieties, doing quite well only found
> 2 w/blossom end rot.  The plants are protected with cages made from 
> concrete re-enforcing mesh five feet high and anchored to the slab
> most plants are a foot above the cages.  BUT MY QUESTION IS:
>  I have a drip system each pot is fed with a ..35 gph dripper.  The timer
> is set for ten minutes out of every hour starting at 11:AM to 4:PM.
> Seems like a lot but the plants wilt if it is set for less.  What is the 
> recommended method? 
> Bob Addison

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