Seeds all germinate, but don't sprout when planted?

[FrankC]

This is my first attempt to grow cannabis: I germinated 4 seeds (all auto-flower, feminized, 4 different strains, from Sensi Seed) using the paper towel method, and all 4 developed a tap root within 1-2 days.



I then planted them in fully hydrated Jiffy cubes, by opening the side of the cube with a scissors and placing the seed inside, root down, about 3/8" from the top.
I then closed the Jiffy cubes, made sure the seeds were covered with substrate, and placed the cubes in a seedling tray, with a humidity dome and a seedling heat mat.
I maintained the temp at about 80F and RH at about 80%.
Every day or so, I dripped a bit of water (tap water, adjusted to pH6.0) on top, and/or put some water in the bottom of the tray, but not too much.
The Jiffy material was always moist on top, never dried out.

But it's been 5 days since I panted them, and there is no sign of the any of the seedlings emerging. Is it too soon to worry, or is something seriously wrong?

[SoOrbudgal]

Hmmm how frustrating they should of been up by now. Maybe the heat mat is too warm? Well bummer if it were mine i'd open up one of those an check out the seed?

[FrankC]

Yeah, I was thinking of cutting one open to check on it, but didn't want to ruin it, if it's just slow to start. I think I'll give them another day, and then do an autopsy on one of them.
Not sure what to do different next time?

[SoOrbudgal]

Well i don't use those peat cubes nor a heat mat but many do. Sound like you did it all correctly but i wonder if it's too warm with the mat on 80f ? It's tough sometimes during cold winter grows to germinate. Those looked like barely a tail so perhaps it's just gonna take longer? Don't give up on them and try some overhead light sounds crazy but give that a shot and keep the humidity dome on keep the heat mat off if you don't see some green by day 7.

[Ckbrew]

I think your temp is to high. Had that happen before. When moving from the pt the tap root is fragile and if damaged can kill the plant. That is why I germinate directly in coco/perlite with out any dome on them. Dig one up and see if there is any growth in the root. If there is, let them run some more.

[Gingerbeard]

Aren't those plugs pretty compact to start a seed? I tried them once with no success. 80° and 80% is me starting a tent grow in the summer. Seeds will still sprout.
5 days is not long to get going. My current got planted on a Sunday and noticed on Saturday. If they are growing in your cube, they may be deeper than a 5 day sprout.
Cutting them open to see what is going on will also give the taps somewhere to go. And as silly and simple as it sounds, even with a showing tap a seed can be planted upside down.

[crucialbunny]

It's been my experience that the wrapping material hinders root expansion somewhat. What I do that works well is to put soil in a solo cup, dig out a well, cut the wrap off a soaked pellet, and put the peat in the well I created. Gives the new seed and taproot a benign medium to start in and then the roots spread easily into the surrounding soil. It is unusual that they haven't sprouted after 5 days but hopefully you'll see them soon. Good luck -

[Bluey]

Temp should be ok at 25⁰C until it breaks ground and once that happens drop daytime temps to 21⁰C for fastest growth. I'd use a higher pH water in Jiffy, but I wouldn't use Jiffy because I've tried and failed germinating in them in the past, 100% failure rate.

You need to cut those bags as stated. They won't break down fast enough to let the roots out....give it a few more days.

🤞

[Rootsruler]

I try and keep my sprouts at 72°.

[FrankC]

Bluey, you wrote "I'd use a higher pH water". I had used pH 6.0 water because I read (at https://www.growweedeasy.com/ph#hydroponic-soilless-pH) that the optimal range for a Coco grow (which I planned to do) is 5.5-6.5. But should I have used plain, unadjusted water for germination?

[Bluey]

Jiffy pellets are really low in their pH that's why I'd use higher than 6. 6 is for coco for root uptake. Jiffy is not coco, I suspect it's peat or similar....roots won't be uptaking till about first leaf anyway

[Gingerbeard]

8 days in and I have been giving straight tap water that runs 8+ to seeds planted directly in coco. I've done this for a couple years because I am too lazy to pH less than a gallon of water at a time and only use a quart. I used the same water when I towel germinated.
Seedlings do not seem to care so much about pH'd and calmag'd water. Although, while giving pH'd water and calmag to seedlings does no harm, adding nutes at this point has a good chance of hurting the seedlings.
Won't be less than a couple days before I start juicing.

[Bluey]

Same here. Never bother pH'ing water for seed germination, it doesn't need it. Just for nutrient uptake via roots

The issue as I understand it with Jiffy pellets as they have a pH of 3 to 4 so when you do get first roots and you're pH'ing 1st nutes at 6 they struggle to absorb the nutes.

[homegrown]

Well FrankC, you have lots of great advice from every reply above. I can agree with all cause I.ve been there, lol The Jiffy pellets are not ideal for growing weed(no idea why the grow supply industry keeps pushing them). They are very compacted once they soak up moisture and cant really expand because their bound with the netting, (which doesn't break down by the way). First and only time i used them i pulled the roots and it looked as if they had a 2 inch garter belt around the base of the root. Next- the heat mat...I think thats much too hot. I have one, love it, but not for initial sprouting. I know i roasted a couple when i started my current grow. I just use tap water until at least two or three sets of leaves. Another thing that is concerning..when you put them in the cubes, you said you cut the side and inserted the seed. Did you loosen the top of the soil in the cube so the seedling knows which direction to go? It may be time to gather some tweesers, tooth picks and other pointy do-dads and dissect one of those pellets to see whats going on. And on a final note, once my seeds sprout, i put them right into coco/perlite in a solo cup with a shit ton of holes drilled in it. Nice and loose and hard to over water. Good luck...hoping for good news.

[crucialbunny]

I use the coco coir pellets and they work much better than the compressed peat. The key is removing that wrap.

[homegrown]

crucialbunny, whats the name of the coco coir pellets?? Not sure if I've seen them in Canada. We have the Jiffy cube type thing, Rapid rooters, and an almost spongy type cube..looks like a sponge(dont like them) and all grow shops have that rockwool starting cubes. The coco cubes would make things simple.

[FrankC]

OK, I finally decided to open up the Jiffy pellets and see what's going on - this is 5 1/2 days after putting the germinated seeds inside.

Three of the seeds had not progressed at all since I planted them - just showing a tiny tap root (barely changed from the photo in my original post), while in the fourth, the tap root had extended a bit. So basically, they stopped growing as soon as they hit the Jiffy pellets.

When looking back at my notes, I remembered that when I first started soaking the seeds on wet paper towel to germinate, I had them on the seedling mat, and the temp went up to 90 degrees overnight - when I noticed this, I immediately put some insulation underneath and the temp quickly went down to 75 degrees. I thought they had survived this, because they all went on to generate a small tap root by 12-24 hours later. But maybe they were dead, but just didn't know it yet.

Thoughts?

Here are photos 5 1/2 days after planting in Jiffy cubes:

[SoOrbudgal]

Man that's a shame i'm so sorry for your cost loss . Well looks like to me they rotted in those jiffy plugs, i hate them i've tried them and same thing happened once to me. Find yourself some small 2x2 cups or get some solo cups fill them with light fluffy seedling mix it's gental an airy. Also pick up some good soil an extra perilite if you plan to go soil grow. That's what my guess is those shitty pellets only thing you did wrong.

[Bluey]

Oh bum.

You could still try and save them..I would try. give them a rinse and back on paper towel and see how you go. Or not.

Seeds will germinate pretty much the same anywhere from 20⁰C to 30⁰C according to some studies, outside of that range germination % success drops. Once sprouted though low 20⁰C's.

[Rootsruler]

Try THIS ^^^^^^

[Gingerbeard]

Seems to me the pellet pressure does not allow the shell to open enough. If you have those under a light, don't. Seedlings do not need light until they poke through. It will help with the heat.
Tough break. Listen to Bluey. Work them on a paper towel and see what happens.

[FrankC]

I'm repeating the grow using another 4 seeds, but this time:

1. I'll be sure to keep the temperature no higher than 75 degrees.
2. After germination, I'll plant them in Coco-Coir/Perlite in a 9 ounce Solo cup**, instead of using Jiffy cubes ***.
3. Would it be a good idea to let the germinating seeds develop a bit further before planting them?. Last time I took them as soon as I saw a tiny tap root. Is it better to let the tap root get longer before planting?

*** A friend recommended using 3" peat pots containing coco-coir, instead of the Solo cups, to avoid transplant shock when going into the final pots. Any opinions on that?

[Bluey]

I go papertowel until tap roots about ½ to an inch long and then straight into final resting place. I think most do what your proposing though. Rinse your coco with a low EC nute with calmag wash say 0.4....first nutes no stronger than that on start of first leaf...keep the coco moist with plain water, don't drown it. If you get green algae on top stop watering for a bit. It will first show on the perlite a light green tinge. pH 5.9 should be good

Edit. Make sure you maintain 100% humidity till it sprouts and opens then take your lids off the domes about then for 80% humidity, or there abouts

[Ckbrew]

I soak them in tap water for 24 hours then put directly in coco/perlite in a solo cup. Be sure to cut drainage holes in the cup and keep the coco moist until they break ground. Then the plant and all the coco are transplanted into final pot. Transplant is usually after the first root tips poke through the drain holes. I don't like the paper towel due to the possibility of damaging the tap root, which I have done several times.