The germination temperature requirements remain the same regardless of the source of the heat. Al

Air temp doesn't equate to soil temp. Soil temp required for germination will be much lower than the air temp which is why we use heat mats to raise it. So they may germinate - eventually - if they don't rot first.

You can always try the alternate sources of bottom heat often discussed - top of the fridge, top of the water heater, top of the TV de-scrambler, etc. ;)

Remember that light isn't necessary for most seeds to germinate. Warm soil temperature is.

Dave

Al
Thanks
Dave, I am not sure I understand your answer. "Soil temp required for germination will be much lower than the air temp"? Do you mean that ground soil temp is not the same as air temps? That part I would understand, but we are talking about seed trays setting inside the house near a window. Would the soil temps it the trays be that much different from the room temps? I just will have too many trays to start putting them on the fridge etc.

I rarely use a heat mat for starting my seeds, and i usually have good luck with most. I think that as long as you can keep the air temp up, and keep them moist (use room temp. water to water) than the soil temp should stay at a fine temp. Good luck!!!

you will be fine with what you have. 70 degrees is a good temp for most seeds. Heat mats would be a waste of money.

check out my blog this will show you my setup

Here is a link that might be useful: Gardening by the Seat of my Pants

Would the soil temps it the trays be that much different from the room temps?

Yes, they will. By approximately 10 degrees lower in the soil. Basic law of heat convection/transference. Heat moves through air much better than through soil, or in this case damp seedling mix in plastic.

Every year about this time we get into lots of discussions on this forum on the need for supplemental heat for germination and the two camps - yes and no - line up their ducks in a row for debate. ;)

Bottom line, can you get germination without the use of supplemental heat? Sure. It is just slower and at a lower rate so some seeds are wasted. Is it faster and and do you get a higher percentage of germination with it? Definitely. Ample research and many documented studies prove it.

But convenience and $$$ play a role too so if you can provide it - great. If you can't and are happy with the results you get - that's fine too.

Dave

I have a shop-light/8 tray set-up for seed starting. The seeds that need heat to start, I put under, or on top of, the fluorescent light fixture where the heat-producing "works" are. Feel the fixture and you'll find it. It works everytime and you don't need a mat. Watch it carefully on the top of the fixture because it can get hot.

Just to add, standing next to an outside window is generally the coldest spot in my house...

Yes I agree with sleepy the window is the coldest place. Never-the- less I did start seeds for many years in my south facing window.

Seeds do not have to be in a window until they sprout. Before I had my greenhouse and heating mat, I started mine with a small cake rack over the forced air heating rad.

I bought a few clear Croissant boxes from my grocer for 50 cents each. With their clear lids they are perfect for starting seeds. I held them together with a clothes pin because some of the buttons on them stick and are hard to undo. I use plastic mushroom boxes that I put holes in the bottom of to put the soil in and 2 of them fit in the croissant box, which fits nicely over the rad.

I still use the clear boxes and mushroom boxes in the greenhouse and on my heating mat.

Thanks for the help. My DIY light rack has 12 fixtures/24 bulbs on it already. I already use the tops of the lights for bottom heat so I was just looking for more ideas. I planted some seeds last week and put some on the light rack in the garage and some inside with no bottom heat. The trays inside are already starting to sprout some seeds. It has been so cold inside the garage that even with the bottom heat the trays are not yet sprouted anything. This year I am keeping good records on everything I plant.

I use the top of my computer that runs 24-7 and my wireless router also. Both stay warm\hot all the time for quick germination; even better than my water heater.

It looks like those on the inside in the sunroom with no bottom heat and those in the garage with bottom heat are all germinating at about the same rate. Looks like I will have more plants than I can handle.
Outside

Inside
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as was stated above this debate happens every year if bottom heating is necessary. My results with a constant room temp of 70 gives me great results. An example is my geraniums. Within 48 hours I had germination and 24 hours later all 40 seeds had germinated. I think bottom heat is just one variable when it comes to seed sowing.

Just my opinion

Here is a link that might be useful: Gardening by the Seat of my Pants

I think Al responded first by saying that it doesn't matter if it is bottom heat or just heat it is all the same. I can't see any difference in my trays. They are all sprouting.

IME, it depends on the type of seeds I am trying to germinate. Peppers and tomatoes seem to do much better with the soil at about 80-85. Lettuce does better when the temps are in the 60s or low 70s. I haven't figured out what bananas want - I'm ready to try 20 below, I've tried just about everything else.

Mike

Mike,

"I haven't figured out what bananas want..."

Where did you get banana seeds? Most, if not all, "grocery store" bananas are triploids, and hence sterile, because seeds of triploids are not viable.

ZM

From banana seed sites! I have about 22 different types, none of them seem easy to germinate, at least not in 8-10 weeks.

Balbisiana Banana
Giant Nepal Banana
Thomson's Edible Banana
Royal Sweet Banana
Giant Yunnan Banana
Musa Coccinea ( Scarlet Banana )
Musa Ensete ( Ethiopian Banana )
Musa x. Paradisiaca ( Dwarf Cavendish Edible Banana )
Musa Rosacea ( Flowering Rose Banana )
Musa Velutina ( Velvet Pink Banana )
Musa Zebrina ( Striped Banana )
Darjeeling Banana Musa sikkimensis
Red Flash Banana
Thai Gold Banana
Dwarf Indian Banana
Cheeseman's Banana
Abyssianian Banana
Monkey Fingers Banana
Cold Hardy Banana
Ensete glaucum (Snow Banana)
Ensete ventricosum
French Banana Musa Paradisiaca
Violet Banana Musa Violacea
Thailand Rock Banana Ensete Superbaum

Mike