From

Location

Message

Date Posted

Florida

Hello, new member here. I have started some tomato seedlings (36 of them) and I have a heat mat/thermostat under them. I have seven that have germinated today. I have heard that you should remove the heat mat when the seedlings start to germinate and begin using the grow light. My question is if I should take them off the heat now with only seven germinated seeds, or if I should wait until more germinate. Thanks for your help!

2/8/2018 11:37:09 AM

President - GPC

Create two separate chambers. Sounds like you dont have a grow light over the germ chamber. Tomatoes are sensitive to temp changes too soon, so I would have two chambers, one germed one still crankin and hand pick over to the new grow chamber which you can vent and change humidity slowly. I use grow lights to also heat the soil. Light does penetrate through the soil to assist with strong germinations. T5Badboys 8 tubes 500W on the germ table for me. You can get these from the WOW store.

2/8/2018 11:50:01 AM

Oak Grove, Mn

You will probably get a few answers here for the best way to start seedlings. I know I have tried many different things. I am wondering what temp are you running the heat/mat, what temp is your growing area and what media are you starting in.

On a side note..I see we have a Florida grower. I have had several emails in the past few weeks wondering what is a good seed/and or variety for growing in the southern states. I glanced at the tomato statistics..couldn't find any over 6 pounds that came from the south. Any ideas anyone?

2/8/2018 12:02:18 PM

Florida

WiZZy - Thanks for the reply. I'll give that a try.

bnot - I set the thermostat to 80 degrees, but it runs anywhere from 81-83. The ambient room temp is around 75. The were started with Jiffy mix (not peat cups or pellets) in plastic cells.

2/8/2018 12:16:00 PM

Lebanon, Oregon

Exactly what Wizz said. With heat still cranked up the seedling will get tall and spindly in no time. I was out of town a few days, went from nothing to 2-3" tall tipped over spindly seedlings when I got back. What a pain to try to save them. I do soil temp. 88-90F. When a few emerge I put a CFL 60w right on top of them. It's a cooler light but enough to keep soil warm enough to emerge a bunch more seeds over the next few days. I remove and carefully transplant the larger one's to another chamber. You have to think ahead and be right on top of this process or you will have a disaster. Practice, practice, practice before you do the real thing.

2/8/2018 12:48:03 PM

Oak Grove, Mn

Wizzy, and garden rebel have good answers. One difference...their choice of grow light. What do you have available?

2/8/2018 1:02:44 PM

Lebanon, Oregon

...I do transfer the small seedlings to my pump house (I do not have the indoor grow operation space you have) and put a 300w LED light hanging over them. They really like that. I do have some smaller 50w LED's. Would you use the LED's instead in the beginning? I know you are the light guy.

2/8/2018 1:48:04 PM

Oak Grove, Mn

I have not tried the cfl's so am not real sure how they compare. I go directly to an LED or my ceramic metal halide. If neither is available i will use a T5. I have cooked seedlings before, not from heat but from light intensity. You probably could save yourself some effort rebel and go directly to led..you might have to experiment with heights. My 300 watt LED will probably put out a different PAR number than yours. So we cant really compare height above canopy and say this is how high it should be. You were talking about lanky...i have most issues with lanky when i use the t5. Light intensity will keep a plant short ie my 4 inch tall plants blossoming. To get that intensity with a t5 is a balancing act...heat vs light output.
I was asking about what light this grower has available. I think can be successful with about any of today's light choices. Just would have to compensate for the differences.

2/8/2018 2:01:59 PM

Oak Grove, Mn

I am wondering..if his ambient temp is 75 if he really needs to use the heat mat. I know I have had +90% germination rate using the paper towel baggy method..with the bag just placed on my desk which is usually about 75. I am thinking that removing the heat mat..might cause an extra day before germination..but is it going to do more. The other thing that caught my eye..it sounds like he is germinating in starting media in what i am guessing are the starter pack trays. Moving an individual plant from there to another area without moving the whole tray, might cause root damage.

2/8/2018 2:33:04 PM

President - GPC

Agreed Bnot, should ask what his planting medium is..

2/8/2018 3:11:09 PM

Newcastle, CA

I keep my heat mat cranking 24/7.

my full grown indoor tomatoes still use the heat mat. my plants are not leggy.

2/8/2018 5:23:15 PM

Newcastle, CA

Also, based on my online research you may want to try grafting your tomatoes to eggplant rootstock; it may help with your humid environment.

2/8/2018 5:30:37 PM

Oak Grove, Mn

I think you might be right Austin. Thinking about it..my hydro starts before they get moved to a bucket develop at about 85 degrees. They don't go leggy. I think leggy is a matter of light intensity...they plant is growing to find light food. There are two problems with leaving on heat mat. 1. chance of root burn...my heat mat goes from really hot to off..the sensor does not measure from absolute high and low temp. 2. From this last winter start..I have noticed that the plants in 70 degree DWC temp have developed about 50-70 % faster than the buckets that are running about 85-90 degrees. I can attribute some of this to the increased oxygen capability of cooler water to hot water. Maybe there is a correlation to plants in soil?

2/8/2018 5:39:42 PM

Oak Grove, Mn

Austin..i suggested to another grower in the south..that he might email you to discuss the nuances of growing in heat..I hope you don't mind.

2/8/2018 5:42:08 PM

Newcastle, CA

We'll see if I get anything to grow that is noteworthy! I don't mind. The weather here is in the 70's already! :0

2/8/2018 5:49:32 PM

Newcastle, CA

yeah I think legginess is all about the light.

2/8/2018 5:50:27 PM