Failed Germination in Propagator with Heat Mat- Soil dried out

I tried germinating my seeds last Friday at 9.30pm using the Royal Queen Seeds Starter Kit. I put the perlite at the bottom of the tray evenly, soaked the starter cubes in a container of warm water with RQS’s beneficial bacto for 10 seconds, put the starter cubes on the perlite in the tray, and put 3 seeds in (two in the 2nd row from the bottom (one in the 2nd from the left, and the 4th), and one in the 3rd row from the bottom in the 3rd pod).

I put the propagator in my grow tent on top a heat mat. In the pic it shows temperature at 20 degrees Celsius, but after a while this went up to 24 - 26 and stayed there.

Sunday morning, one of the seeds was pushing the seed out of the soil. Monday at 5pm after work, I checked on them, and the starter cubes were bone dry :frowning: The ones that are dark brown while the others are very light brown is because some of the condensation dropped on them when I moved the propagator to check on them after panicking and seeing it so dry. You could even see the little baby that was sprouting in the dry pics below (the 2nd pod from the bottom and left). I opened it up and moved the starter cubes, and the perlite at the bottom was crispy and not moist AT ALL.

Can someone please help me in germinating properly with this propagator? I followed RQS’s instructions to the letter, they even state to not water anymore after the initial soaking of the starter cubes. Did this happen because I added a heat mat? Is the heat mat too big for the propagator? Do I need to periodically moisten the starter cubes even though RQS says not to?

Any help would really be appreciated. I’m new to this and already lost 3 seeds :frowning: I feel so disheartened that my first 3 babies are already dead. I imagine that the 2 that didn’t sprout yet are probably dead too :cry:

Thanks in advance to anyone that pitches in.

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@MagicCultivator420 I am not familiar with the RQS starter kit and instructions but I can tell you from experience when using the heating mat and germination…watch it carefully because it can over heat things…I typically only need the heating mat during winter months and I put a towel between the mat and my germination dome to keep the damn thing from cooking the seeds…


I don’t use that system but since it was so cold here I put my tray on top of an upside down laundry basket (I don’t have a heating mat) over a heating vent. My clones dried out. I have moved it to my desk and will just deal with slow germination/propagation.

I have also started pulling out the cubes individually and spraying the sides to keep them moist but not wet.


Hello, thank you both for your prompt replies.

@Retiredoldguy I was thinking of using bottle caps to elevate the propagator from the heat mat instead of a towel. Won’t the towel be a fire hazard covering something hot like that continuously? How often do you re-moisten the cubes with the heat mat on? Mist or water? (I have a dosing syringe if need be)

@JaneQP Slow germination or will the cold inhibit germination completely? Everywhere I read states that cannabis seeds need at least 21 degrees Celsius to germinate, it’s 17 to 18 degrees in my tent currently. Can I mist or water the top as I asked Retiredoldguy? Wouldn’t feel too comfortable only misting the sides.

Thank you again both for answering so quickly.

I also mist the tops of the cubes, the plants and the inside of the dome. I have been cloning and dropping seeds since December. I do the spray on the sides because I started noticing dry spots. Temp is sitting around 71F and humidity 67%. Before temps on a side table near a window were 68F.

This is what works for me. You will find what works for you!

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I germinated two CBD plants. Some dill and parsley from seeds. Clones are not fairing as well but they came from sick plants. Maybe 50% survival rate.

I’ll have to do the conversation to C. All I know is 0C is 32F and 23C is room temp. So 17c is 62f. Might be a bit chilly. I think the bottle cap approach may work. I also wrapped my dome in aluminum foil hoping it would reflect my more light and heat.

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Hello again @JaneQP I tried elevating the propagator with bottle caps, temperature is a stable 22 C (72 F) now. I will try planting 3 new seeds and mist or water them daily or every 2 days (depends how dry I see the medium is getting) and hope for the best. Wish me luck, and thank you for your replies :slight_smile:

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Best of luck to you and I hope they all sprout and you grow some big plants! Keep us updated!

I have to spray mine twice a day. We have very low humidity here.


@MagicCultivator420 I use the towel because it insulates the right amount for my application in winter…bottle caps would work too but since air will flow under your dome it will be cooler than if you used my towel technique. The mat does not get hot enough to ignite a towel. Since I grow in rockwool and DWC my cubes are in the dome and I keep enough water in there to promote moisture on the walls of the clear dome. don’t over water just enough to promote moisture. you will have to watch your setup and adjust moisture as needed daily.


@JaneQP Thanks, I will keep your misting suggestions in mind. Thanks again for all your replies.

@Retiredoldguy Thanks also, I left the propagator on bottle caps last night and today morning the temperature inside it was 22 degrees Celsius, so hopefully that should help avoiding the seeds from cooking this time.

Going to try a pre-soak for around 20 hours today in a glass of water before planting them in the starter cubes in the propagator tomorrow evening. I will keep a close eye on moisture this time around. Thanks for your assistance also.

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@MagicCultivator420 presoaking has its place but be careful because fresh seeds can drown in 20 hours in water…I never go more than 6-8 hrs soaking before placing in the paper towel with the 2 plates forming a dome…watch to see if the seed cracks and if it does get it out of the water and into the paper towel…I say paper towel but I see you are going straight to the grow medium and that is ok and will work

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@Retiredoldguy Oh, wow, thanks so much for that really helpful advice. Last thing I want is to kill another 3 seeds. I’ll take your advice and leave them 6 - 8 hours then. I wasn’t planning on letting them crack in water, just enough to let them soak up a bit and move them to the starter cube where they will hopefully crack in there. Or is that a bad idea?

@MagicCultivator420 what you plan to do will work…I just prefer to see the tap root come out and then place it in my rockwool cube…just another way to do this germination task…you will develop your way as you read how each grower does their grow…and from your own mistakes which are going to happen

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Thanks, glad to know it will work. I’m planning on moving the seed to the starter cube before it cracks so I don’t risk damaging the tap root, trying to play it safe as much as possible. Hoping for the best this time round. Leaving work in 15 mins and gonna go drop some seeds in water :slight_smile:

Yeah, I’m realizing that, there are soooo many different versions reading about all this, everyone has their own way of doing it. Yeah, we learn from our mistakes, already got one under my belt with the heat mat frying everything… Lesson learned though, treat heat mats with caution.

Thanks again for all your informative replies. I really do appreciate everyone’s help here.

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Hello again,
so last Thursday at 7pm, I soaked my seeds for 6 hours, then tranferred them into the starter cubes. I made sure to keep them moist this time by misting them twice daily, and today morning I am seeing progress. The only problem is, the root grew up out of the soil.

Should I do something to help orient it? Should I just wait? For now I just covered it very lightly by breaking a piece off of one of the other cubes since my propagator has a light and the radicle is sensitive to light.

I’m also thinking that the problem could be that since I was misting the top, the top was more moist than the bottom due to the heat mat, so the root went up instead to seek more moisture from the top?

Any help would really be appreciated, I don’t want to lose these babies again :frowning:

Update: I split open the starter cube gently and transferred it to a new cube with the correct orientation. Hoping for the best. If anyone has a any ideas as to why this happened it would be great to avoid it in the future.

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I have never seen that before.

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Hello JaneQP, thanks anyway for takin the time to reply. I’m going to wait a couple more days to see if the ones with upside down roots pop their heads out. If not, I’m going for a few hours pre-soak, then continue with the paper towel method and then into jiffy pellets. Getting too many issues with my current germination kit.

I use the root riot cubes. I dropped two seeds and they did fine. I have quite a few clones. I have a tray with a dome and a T5 light. I use those small six pack planters to support the cubes.

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