I can't get my head around my electric propagator!

So I'm having a spot of bother and I'm wondering if anyone can advise me. I'm a beginner with this bit of kit which is the Stewart Heat and Grow Variable Temperature Electric Propagator - just in case anyone else has got the same one.

So I put some moist sand in the bottom with the sowed seed trays on top of the sand, put the lid on, closed the vents in the lid and set the temp for 20C. It's in the house on a table. I switched it on but the base didn't get warm. I left it a good few hours.

I decided to turn the temperature up so when the dial on the temperature controller hit 24C the red light on the temp controller came on and the propagator base warmed up. I checked my seed packets and the optimum temp for germination is 15-20C. Does this mean then that 24C is far too high? And does it matter to the germination of the seeds? The soil is warm, it's not boiling hot or anything! There is condensation on the inside of the lid now but there wasn't any at a temp of 20C.

Should I just turn the temp back down to 20C? Should I be able to feel that the soil is warm because last night at 20C it wasn't even a bit warm? Is the fact that because the radiators have been on in the house because of the snow, meant that the temp of the propagator has to be set higher than the temp of the room before it will come on? I'm confused!!

Thanks.

 

Hi John

Yes the central heating was going in the same room as the propagator but when it didn't switch on, I turned the radiator off but the propagator still didn't warm up. The CH thermostat is set to 21C and sometimes higher but the door to the room was open and the radiators in the rest of the house were on.

Looks like a thermometer would be a good idea. I'm not sure if we are supposed to do it but can you recommend one?

 

I think this proves you dont need a propagator, at least during the day when the heating is on, but at night the thermostat might well switch on, so its still a good idea.

Seed germinaton temperatures are only a guide and as John says a few degrees either way for most seeds is not a problem.

 

Hi Fern , I propagate all my seeds in the house. As a rule of thumb if the germination temperature is 15°-20°c that is generally windowsill temperature . For the ones that call for 22-25°c I use my basic Super7 heated prop , which has no thermostat. I like to think that a daytime nighttime temp fluctuation possibly helps the seeds.
The only seeds you will have a problem with are the ones you really want to grow !

 

Hi Fern, Its because the temperature in the room is higher then the setpoint on the propagator - also most of these are not 100% accurate and could a few degrees out.
In a normal heated house room you wont need a heated propagator.

 

I've wondered about this. I wonder if the seeds would benefit from bottom-heat, rather than just getting a steady central-heating-created 20C ? Perhaps set a propagator thermostat "up" and stick it on a 15mins-on 15mins-off timer?

 

Thanks everyone,

I must be doing something right as my French Marigolds have germinated in 2 days. Although as a beginner I'm not sure if speedy germination is a good thing or not - they look ok!

Hi John, I've been checking thermometers out - thanks for that.

The French Marigold seeds are past their sell by date but I thought I would try them thinking that it wouldn't matter if nothing came of them while hoping that my agastache seeds would be really successful. No sign of anything from them but two days even by my level of impatience is a bit quick!

 

Plants vary ... some that I am trying to get to germinate need a period of warm damp, then into the fridge for some cold, then more warmth to germinate. Some will still not germinate and need another period of fridge and repeat of warm (so called "double dormancy"); this is natures way of spreading the germination to give the seed the best chance of growing, and of growing at just the right time.

Some Lily seed puts down a root (i.e. this is all underground) and starts making a little bulb, all with the energy stored in its tiny seed), and its only the following year that it puts up its first leaf. With those you have no idea if Year 1 has worked, or not, until Year 2 - very frustrating!

Lots of seed that most people grow routinely germinates pretty much by "just looking at it" so to speak. Some of it quickly (a few days), some of it a bit slower - Parsnip and Celeriac seed tends to take several weeks.

I keep a list of germination times so I know what to expect - it helps me arrange things in the propagator etc. that will germinate at the same time, and some things (Amaranthus springs to mind) grow leggy SO quickly that they need to be under bright light before they germinate to reduce that effect - again, knowing whether its 1 day or 2 weeks helps with organising that

Don't know about you, but my next-generation daughters are obsessed by Sell By Dates on food - they seem to think that eating something one day past its Sell By Date is going to kill them!

Some seeds are known to have very short viability - Parsnip seed that is two years old will have very low efficacy. But for lots of seeds they last for ages; particularly if in an unopened foil packet from the supplier, and if kept in the fridge (but not frozen) in an air-tight Tupperware box. (Its very important that they are dry)

I have found Tom Clothier's site useful for germination times. He lists a few different Agastache that he has tried, so you might want to check your varieties in case he has suggestions (I note that for Agastache scrophulariaefolia he has put them in the fridge first - hopefully that's not the variety you are growing!)
http://tomclothier.hort.net/page02.html

The other site I find useful is B & T World Seeds
http://b-and-t-world-seeds.com/alaCarth.asp?searchFor=Agastache
if you pick the variety you are growing you may get some germination information at the bottom of the page. Its a bit hard to digest! watch out that there is usually some generic information followed by some variety-specific info - which can completely disagree with the generic info, and is often very terse. So you might just see "21C" or somesuch on a line by itself, at the bottom, that tells you the germination temperature

Take Agastache foeniculum for example:
http://b-and-t-world-seeds.com/cartall.asp?species=Agastache foeniculum&sref=3189
which says:
"Agastache foeniculum seeds will usually germinate in 30-90 days.
Sow Agastache foeniculum seeds about 2mm deep in a Well drained seed sowing mix at about 12°C"
(which is a lot less user-hostile than the example I gave earlier , but I find that the "readability" of their information does vary a lot on their site)

P.S. Make sure you are on the "Information page" for the variety, the Buying page doesn't have the germination info, but it will have a link to the "Information page"

 

Oh should I take the French Marigolds out of the propagator now or should I wait a bit longer and leave them in there?

 

Thankyou Kristen for this information. It's much appreciated. I will check out the links you have provided. At the moment I'm trying to stick varieties which seem straightforward for a beginner and as my confidence and experience increase, I expect I'll be more adventurous in my choice of seeds.

 

Just to add to the thermometer part try one of these inside the propagator to see what the inside temp is like. I use them in my Jemp and they help me out with germination temps.

http://www.amazon.co.uk/Test-West-M...1AXA/ref=sr_1_2?ie=UTF8&qid=1364382333&sr=8-2

I do put one in each tray though.

 

Thanks landimad I'll have a look at the link.

 

Personally Kristen, with most common seeds, I cant think it would make much difference either way.
If you are germinating bedding plants for instance, most are not really that fussy as long as its reasonably warm.
Some of the harder to germinate exotics, yes could be important.