Hillbilly tomatoes

Bill Shoemaker wshoemak at inil.com
Tue Aug 7 09:51:43 EDT 2001

>-  When we water, we use a 'long' hose with a watering wands at the end and
>then run the water directly into the plant/plastic hole
>-  Had been watering every 3-4 days, for about 5-7 seconds per hole
>Given a situation of no rain for quite some time, should we
>1.  Water more or less frequently?
>2.  Run in more or less water each time?

It is incredible how much water is consumed in the field in the summer. An
inch of rain is 27,000 gallons/acre. When temperatures are in the upper 80's
or higher, water consumption is around 0.3" per day or more. Another words,
that 27,000 gallons is good for about three days in this weather, then
stress sets in. If your soil has a great water holding capacity (silt loams,
silty clay loams) it might hold up to 1.3" of available moisture per foot of
depth. If your crop can effectively reach 3' down there should be 4" of
reserve moisture there. But in a season like this, that can be used up in
July when demand exceeds availability more often than not. That is why an
abundant supply of water on demand is perhaps the key to growing abundant,
high quality vegetables and fruits.

In terms of frequency, I like to water thoroughly as seldom as possible.
Right now I'm irrigating (through drip) about 1" per session twice a week.
In this weather that's just enough. The tomatoes have a full set, are still
growing and setting fruit and the fruit are sizing up beautifully. Peppers,
Melons, watermelons are the same. In fact all crops respond to water
management like this, more so than any other management practice.

In direct answer to the two above questions, I would water at least once
every two days if not each day and apply a little longer each time. While
you're using plastic mulch and have good moisture holding capacity, water
will move laterally away from your plants to drier soil, eventually becoming
unavailable to your tomatoes. That's why you need to continue application
frequently. Try watering a set of ten plants at twice the rate of others and
look for a response.

Bill Shoemaker
Sr Research Specialist, Food Crops
Univ of Illinois - St Charles Hort Research Center

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