Seedlings dying fast

[Perran]

Hi! I've been following threads and grow logs with confidence of how to spot problems and overcome them. But it all went wrong somewhere...

My grow is simple,
Light from sun only
Feminised White widow/ bubblegum seeds
Germinated in tissue and planted in compost.

I started with 70 seeds, now I'm down to 30 and next week I'll be less than 10 if I don't fix this. I really appreciate your help

From the pictures I can predict a number of problems but cannot work out which it is,

1) LIGHT
They are all on a north facing window with no direct sunlight causing the plants to stop photosynthesising.
The light meter dosent even register and the plants are searching for light.

2) OVERWATER
They were Watered when planted and the soil is still wet 2 weeks later, maybe the roots are drowning?

3) UNDERWATER
They haven't showed signs of needing water since I planted them and the pots are heavy, so I just havent.

4) NUTRIENT BURN
the soil is enriched with nutrients to help cuttings and seedlings, maybe there is too much for these plants.
I added nutrients to selected plants and they died the next day...

5) PH IMBALENCE
A basic PH meter shows the soil and water around 7.
I don't know if this is tolerable for new plants as I know it's supposed to be 6.2, maybe I'm getting a nutrient lock out.

6) HEAT STRESS
The windowsill is above the heater which came on regularly. I thought this would help keep the plants warm but I may have cooked them.

So there's a lot of plausible possibilities but I don't know which one to work on and loosing plants daily.

I'm looking to move them outside in direct sunlight under a type of green house but temperatures reach 3 degrees at night which could also kill them.

I really appreciate your support guys
Thankyou
Perran

 

[Scientific]

> ...planted in compost ...the soil is enriched with nutrients to help cuttings and seedlings, maybe there is too much for these plants... I added nutrients to selected plants and they died the next day... They were Watered when planted and the soil is still wet 2 weeks later

Hi Perran. Sorry you're having problems. (I feel your pain--had some grow problems myself lately...)

I'm guessing that the two biggest problems are your compost doesn't drain well enough and may have too many nutrients for delicate seedlings. I would suggest starting with a top quality commercial potting soil (with no added fertilizer) that drains very well (adding 30% Perlite seems like a popular route). Fox Farms soil seems to be very popular.

> The light meter doesn't even register and the plants are searching for light.
Well of course you've gotta have lots of light. Does your light meter read out in lux? Cannabis thrives at 50,000 lux or more. That's the same level as out in the garden on a sunny day. (Just for reference, a seedling that has been out on my deck in the cold and the rain for over a month looks happy and healthy, but it's still only two inches tall when it's younger strainmates getting lots of artificial light indoors are already blooming. Ya gotta have photons!)

> HEAT STRESS
So how warm is the plant area at its warmest when the heat is on? Over 80? (I'm going to guess that unless they're really close to the heater, heat isn't the problem, but there are limits even to what a hardy weed can withstand.)

Sad to say, but I think maybe the best thing to do at this point is to start over with fresh, top-quality, well draining soil and plenty of light.

Good luck and have fun!

 

[Perran]

Hey Scientific, thankyou for taking the time to respond in detail
I have a basic PH meter which measures ph, moisture and light.
So it won't be the most accurate but it does give me an idea.

I agree, Light and water are the most important things for plants so maybe I could save the healthier ones by transplanting them outside, that way they have natural unfertilised soil with good drainage and lots of sun.

They did get hot when the heat was on which may not have helped but I'm feeling lack of light is what's stunted the growth.

UPDATE...

oh I've just discovered something interesting...
Remember I said next week I'll be down to 9 plants.
I actually planted 9 mixed Northern Lights aswell. All 9 look healthy.
It's the other bag of seeds that are all dying. So it's something to do with the strain...

 

[Weaselcracker]

Scientific has it covered.

Ignore the ph for now it's not your issue. Lack of light also isn't killing your plants.
Overly rich soil may be stunting them but it won't outright kill them.

Those cheap three-way meters that you stick in the ground - they just don't work. If it's the one I'm thinking of you may as well toss it in the garbage now because you'll be doing it later anyway, like everyone else who's ever bought one. Unless you can think of some other use for it like as a meat skewer or marker stake. Or perhaps you can use it as a weapon to rob the bank or corner store to get money to buy a better meter.

Soil being too wet is the #1 killer of seedlings. In fact it's about the only thing that will kill them quickly other than extreme temps. Your plant will grow best when the soil is almost dry. It should be just barely moist - spongy feeling.

 

[Perran]

Hi weaselcracker.
That's great advice and very conclusive thankyou.
So if the soil is too wet and dosent dry out naturally, how can I get it to dry please?

 

[Weaselcracker]

Good question. Pretty difficult. Given that you've lost so many already, maybe the best you can do is try a transplant, even though some may not make it. Normally transplanting isn't a problem at all- but it is a bit risky when they're very small. They're at a delicate stage- plus if the soil is wet and heavy it tends to stick to the roots and break them off much more easily than dry soil would.
Kind of hard to explain I guess, you just have to wing it. You could try just dumping them out and then try to ease out the section with the seedling and roots in it. Maybe use a spoon or something and try to dig out the middle- or scoop the wet soil away from the sides before easing gently into a pot of drier soil.

Another option is to just stop watering and wait. It depends how wet the soil is. If I thought it was not going to dry out inthe next few days I would probably scoop them out with a spoon and transplant.

Get a thermometer that records high/low temps so you know what range you're actually in.


Lots of info in here including some basic watering info. How to Grow Marijuana Everything You Need to Know

 

[SageGrower]

So if the soil is too wet and dosent dry out naturally, how can I get it to dry please?

You may have missed it but at this point I think you only have one solid option like Scientific mentioned. If you do this quickly and correctly, you may be able to save what's remaining: 1) transplant into a seedling friendly substrate. Assuming you are staying in soil, use soil with plenty of perlite (70/30). Seedlings are already in bad shape so be careful when handling and use mykos (or similar). Be sure to contact any visible roots with mykos.

RTI Xtreme Gardening 4402 Mykos, 2.2-Pound Bag

 

[wiley420]

Try a fan blowing across the top of the pots this might help dry the soil out a bit faster

 

[Perran]

Some great pointers thankyou.
With the hours of research I've done on all the technical stuff I never paid much attention to simple things like watering!
I will section the plants and try some different tactics, then I can post in the next week or so if anything worked

Thanks for the fast responses,

On a side note im still intrigued at how all the northern light strain seems unaffected by this...

 

[Scientific]

So if the soil is too wet and dosent dry out naturally, how can I get it to dry please?

If I may jump back in, it looks like you have two related problems: poorly draining soil and soil that's too wet. The problem with poorly draining soil is that by definition it's hard to get it to dry out AND often poorly draining soil when it does dry out dries to an impenetrable, brick-like consistency.

If you want to try to save the ones that have a chance, I would suggest very gently scooping them out of the pots with a spoon and repotting them into better soil. If you do it very carefully the seedlings may well recover very quickly. You didn't say that your plants were autoflowers, so they're not on the automatic flowering countdown clock and I would expect could come back to 100%.

Good luck!

 

[Weaselcracker]

Watering is the most important thing to consider - especially when they're young. My entire life revolves around how often I have to be at the grow to water it. Around five days is a good wet-dry cycle time frame.

 

[Perran]

I had another look at my grow medium which is peat based designed for germination, that would explain why it's retaining moisture.
I think I was supposed to transplant as soon as they popped.
Better get on with it...

Your right scientific they are not auto flower so I have time to turn it around

 

[Weaselcracker]

Peat moss on its own should drain reasonably well- not that you can't easily overwater it. Peat moss on its own isn't soil. Do you have more details of the 'soil' ingredients?

 

[Perran]

Does that help?

 

[Weaselcracker]

I guess if it's got compost in it then we can call it soil. Maybe if you added 30-50% perlite it would work better.

 

[Perran]

Thankyou for all your awesome input guys, really appreciated

I still don't know what the problem was but I ignored then for a few weeks and after a really sunny spell they are living it!
I guess you need a lot of sunlight to grow without lights.

As for watering I just havent. They are only now asking for water and I give them only what they ask for lol

 

[Clean as a whistle]

Ahh. Beautiful