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Re: Yellowing Seedlings/Plants

Hi Toni,

> I used "Roots" to begin with.  Now, I give the tomatoes/tomatillos Miracle
> Gro for tomatoes.  The rest get regular Miracle Gro.  1/4 tsp. per 2 gallons
> of water every time I water.

Should be okay.  Sounds like a pretty dilute solution.  Is that 1/4 strength?

> The puzzling part here is that I have 2 separate shelves set up for my
> seedlings.  The shelving unit that has the yellowing problem has 3 sets of
> lights, total of 6 48" bulbs, 3 cool, 3 warm.  The other unit, which doesn't
> have any yellowing problem has just 2 lighting units, same 48" 2 cool, 2
> warm.

Hmm, there's a clue here - Am I safe to assume that the shelf with six bulbs is
the lower shelf of a tiered setup which is sitting on the floor, perhaps in
your basement? If so then it may be a temperature thing.  The plants on the top
shelf are being bottom heated by the lights underneath it, but the bottom shelf
isn't getting any bottom heat and is sitting in the cool air which pools on the
floor.  Maybe you should put the heating mats back under the plants on the lower
shelf.  Or, if that's not possible for lack of heating mats, you could raise the
whole setup up off the floor on a few cinder blocks you'd have room to put a
baseboard-type heater underneath.  Just a guess, but may be the problem.  I've
seen how cool soil makes it difficult for plants, especially young seedlings, to
absorb enough nutrients.

> << While 12 hours is okay, much like the outdoor's daylight length, 16 hours
> will give your seedlings more energy and encourage better growth.>>

> Geez, where do you live?  We don't even have 12 hours of sunlight yet!!!
> :-)))  Even in the summer we won't have 16 hours of sunlight!  I did increase

We're days away from the spring equinox, when nearly everwhere on earth should
be having 12 hours of daylight and twelve hours of darkness.  Where are you
living Toni?  Maybe it's cloudy there.  ;-)

> the timers to 14 hours.  I thought maybe I was giving them too much light as
> I had them on for 18 hours per day.

Anywhere in the 14 to 18 hours range is alright.  I like the 16 hour cycle.

> << Overwatering can leach out nutrients, particularly nitrogen and (I think)

> I may be a bit over zealous in this area, but thought since I have some
> fertilizer in the water it would be ok.

A good trick for knowing when to water, besides waiting for your plants to wilt,
is to lift the container and judge it's dryness by it's wieght.  Often things
look dry when they still have enough water.  Little plants don't need that much,
especially in cool conditions under florescents.  They do need to get some air
into their root zone though.

> I put a small fan in front of the shelving units for a few hours each day to
> help with air circulation and to increase the stem strength.

Good one.

> Thanks so much for your help Bob, I really appreciate it.

You're welcome Toni!  I hope your babes green up again soon, I'm sure they will
as they're a good size already and shouldn't be set back too much by their
experience.

> Toni

Cheers, Bob

   ____________________
  |                    |
  |     Bob Carter     | Kootenay Bay, BC, Canada
  |  bcarter@awinc.com | Zone 6b
  |____________________|


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