From: klier@iscsvax.uni.edu
Newsgroups: rec.gardens
Subject: Re: illegal plants--lobelia
Date: 8 Apr 92 11:38:33 -0500
Organization: University of Northern Iowa

karen@synopsys.com (Karen Vahtra) writes:
> While were on the subject of lobelia, I have a problem with
> mine that someone could perhaps help me with.  The leaves are very
> fragile and can't have much water on them.  How does one efficiently
> water them without a drip system?  I can't spray them like I normally
> do because the leaves just start drooping.  Filling up the dirt
> the old fashioned way takes forever and moves a lot of dirt around.

The art of watering is to water deeply and not all that often.  Waving
the hose around for a few minutes is almost a guarantee of growing
shallow rooted plants that will need to be continually watered.
Waving a hose around in a greenhouse will probably get you at least
lectured at by a greenhouse manager -- and maybe fired for repeat
offenses!  Watering, alas, takes time.  In our smallish greenhouse
(ca. 5000 plants), it takes me at least 3 hours to water.  (No, it's
not a professorial responsibility, but when someone fails to turn up
to water on the weekend, you either water or watch half the greenhouse
die...)

When watering houseplants, the rule is to fill the pot to the brim,
let the excess drain out, and dump the excess water afterwards.  Then
don't water again until the soil is pretty well dried out again.  Of
course you have to make adjustments depending on whether you're growing
cactus or some watery-stemmed thing like impatiens...

When watering outside, water the soil, not the foliage if at all possible.
In any case, soak the soil pretty well.  Most people don't have the patience
to hand-hold a hose long enough to do a good job watering a flower bed.
Once you think you've watered enough, dig down into the soil.  How far down
did the water actually soak?  Probably not as far as you think...  I prefer
to soak to 6".  Depends on soil and crop, though.

Unless you are in a prolonged drought, or there is a hot dry wind, or
the flower bed is protected from natural rain (like under the eaves of the
house), you probably shouldn't have to water more than once a week.   Once
I've gotten things through the initial transplant period, I rarely water 
again until August, when things are pretty well overgrown (all right, I 
plant too closely.  I admit it.) and the daytime temps are in the 100's,
falling to 80 at night.   Then the beds might get a watering every other
week or so.  But only if I'm seeing water stress in the early morning. 

If you have mixed beds, with some things craving water and others less
needy, you can somewhat compensate by taking an unglazed flower pot and
plugging the drainage hole with a cork and burying it up to the rim next 
to the plant that is a water hog.  Fill the pot with water and the water
will gradually leach through the walls of the pot, watering the plants
around it.  You can also add a little dilute fertilizer.  This is actually
a very nice technique for tomatoes and prize-winning pumpkins.   

But I still like ooze hose.

Kay Klier  Biology Dept  UNI 

Newsgroups: rec.gardens,misc.consumers,misc.consumers.house