In article ,
Player1 wrote:

Planted some popcorn a month ago and now the plants have 4-5 leaves.
They are tall and weak - most of them have one leaf that has broken
near the stem but is still alive - all those leaves have some white
dust like substance in the thing in the middle of the leaf that
supports it.

The white material is dusty looking, not like cotton?

How many plants do you have? Corn isn't self pollenating.

Also, all but the newest leaves are going brown at the
tips - lower ones the most.
Plants that have limited nutrients may put their energy into the upper
growth at the expense of the lower growth. Leads me to think there is
something wrong with the roots (rot, fertilizer burn, mold). You don't
want fine, heavy, clay soil for corn. Medium to course soils will warm
faster.

Lanky appearance may indicate lack of Sun.

Some pictures:
Plant 1 - http://tinyurl.com/3nnt99
http://tinyurl.com/4jxje8
Plant 2 - http://tinyurl.com/44sobp

The window faces south-west. Fertilized it once, with the one you mix
in the water, didn't help though. May the problem be the cold air from
the window that is open very-very little all the time (0-15 degrees
celsius outside), sunburn (about 6 hours of direct sunlight on the
plants on cloudless days), saltburn, over-watering or something else?
Corn likes heat, Sun, and water. These are the conditions you need to
optimize. Unless someone has a better Idea, I would re-pot into a larger
container (add 20% sand to 80% potting mix", tent (should be available
from nursery) and put outside on sunny days, close window at night (it's
open to reduce humidity in your home?) to increase warmth, only water
the corn when surface looks dry. Popcorn will take 90 - 120 days to
mature under ideal conditions.
--

Billy

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