I'm no expert, but since you will be gradually hardening the plants off, they likely won't even know (gotta love giving plants human characteristics) that there was a change - just a few extra overcast days.

I can't believe, however, that the difference will be $30. You're not using Kwatts on a flourescent light. Unless my math is really, really, bad it should cost less than $30 to run the lights full blast - hence the difference would be even less.

In any event, good luck and post some pictures. Or wait for the next post which states that I'm an idiot and completely wrong (which again I may be - wrong or an idiot).

Andrew

I always have my grow lights on overnight. I use a well-insulated but unheated room with no windows in an outbuilding for my light shelves. Either I can have the fixture ballasts heating the room or I have to have an electric heater running, so I choose to use the ballast waste heat during the coldest part of the 24 hour day. I then run the thermostatically controlled electric heater during the day.

I then switch when I start putting seedlings and transplants outside in my growbox on sunny warm days. Never had any problems with this system.

Good Luck!
-Tom

Here is my math. I have 4 32 watt T8 bulbs and two 40 watt T12 bulbs. That is a total of 168 watts which means 1000/168 means I will burn 1 Kilowatt hour of electricity every 6 hours (give or take a couple of minutes. I will have these lights on of 16 hours for 60 days which equals 960 hours. If I divide the 960 by 6 that means I will need 160 kilowatt hours of electricity at 18 cents per KWH or 160 x .18 = $28.80 versus around $3.00. I know these numbers are slightly tainted because the peak times are in 12 hour intervals. I am thinking of adding another dual T8 because T12 are not common anymore and are harder to find. I will plan on running these at night then till hardening period. I like the heat idea too the lights will keep them warmer when the house is cooler.

I have my lights starting in the afternoon. But we had a power outage for several hours, I forgot to fix the timer. So my lights are running in the over night hours too. I wish we had non peak kilowatt hours. I guess, I should be glad the electrity is on as much as it is. (I hate Ameren.) We are paying .08 a kilowatt hour until May 1. Then we get the high season rates. So rain or shine, the plants must be outside before May to harden off.