Why did my seedlings all die?

damping off

I grow mine in seed raising mix in plastic pots. The cardboard pots are actually very seedling unfriendly. Take way to long to breakdown, unless they are very wet, plus they also seem to suck the moisture out of the soil due to having such a large surface area acting like a wick. After planting my seeds, I give them a good watering to make sure the entire volume of soil is moist, then cover the pots with shade cloth to slow evaporation, and generally they don't need watering again for 2-3 days depending on temps, or until they sprout. Do not cover them with a "humidity dome", lid, plastic film - anything that increases humidity will just encourage fungus. Watering meanly with a syringe or a teaspoon is ridiculous, the soil needs to be moist, top to bottom and side to side. Roots will not grow in dry soil! Think about nature, rain doesn't just fall near the stem or wet 5mm of topsoil to sprout seeds. I achieve germination of 95%+ for over thirty-five years using my methods and generally water them with a garden hose fitted with a rose. Seeds in soil need evenly moist and warmish conditions to germinate, not moisture levels attained by giving water with a syringe or eye dropper or water atomizer or teaspoon. It may work for some, but is not what I would ever consider ideal or ever doing myself. I also would advise against drowning your seeds in a glass of water for any length of time, unless the seeds are 10+ years old and need a little help. Also starting them in paper towel is another method I don't like - too many risks associated with handling that could damage the root. Jiffy pots can work really well, just don't over wet them. Jiffies are easy as to plant the entire jiffy without the need for handling embryonic roots. Another fool proof way that works really, really well is to start your seeds in 2 inch square rockwool cubes, available from any grow shop. Just soak the cubes (first write on them which is which, very hard to do on wet paper!) for a while, I like to do so for 24 hours, then drain the cubes by giving them a few downward flicks to remove excess water. Make a hole about quarter inch deep, or twice as deep as the seeds is in size, place the seed pointy end down, cover the hole with a small piece of rockwool ripped off the side of the cube, firm down this cover gently, place the cube(s) on a plate and bingo! I like to place the cubes and plate in a drawer or cupboard (complete darkness) for the first 24-36 hours, then put them somewhere warmish but out of direct light. All going well, in 3-5 days time, up will pop your seedling. Usually the raising of the "lid" is an indication that the seedling is about to emerge, and when this happens, transfer the cube into a pot/growing system and give them a light source. Planting your seeds during the New Moon or First Quarter of the lunar cycle can help with germination success and I swear by it! I have been meaning to post a tutorial of the "rockwool method" in my diary, "Cannabis Conundrums". so I will do so for you to see. I will try and do it in the next day or so, no later than Tuesday, if you are keen to check it out. I had many friends that too struggled with the germination process successfully, that I researched and developed a method specific for cannabis seeds that is almost guaranteed 100% germination and survival success and is the method I use with older seeds as it is so germination fool proof. Keeping the cubes moist, not wet, is the key to success. If you can feel moisture when touching the cube with the back of your finger, the cube is moist enough. If not, a couple of squirts with a spray bottle of plain water is usually enough to restore optimum moisture levels. So, stay tuned, the tutorial will appear very soon! Hope this helps,.... Organoman.

Hi! My best guess is wrong temperature and humidity and possibly too wet soil. I've had the best growth and survival % with the seeds that I let grow their cotyledons before even transferring from paper towel to soil/rock wool. For some reason when I transfer after tap root is grown, they tend to die before even actually starting to grow properly. Humidity is very important part in seedling stage (And through out the grow tbh) and it should be atleast 80% but preferrably 90% until first leafs has grown. If the soil is too wet for too long the oxygen will run out and the roots will suffocate and this will kill the plant.

Overwatering almost guaranteed. They don't need much and too much drowns the roots causing the seedlings to "damp off". Make sure your drainage is good and you're waiting for the topsoil to dry before watering again. It's usually better to water less more often. So if you are doing 100ml every 4 days, consider trying 50ml every other day.

Are you drowning them?? Seedlings don't need humidity to grow.. They need water in the soil to transpire and grow. Clones need humidity.. But seedlings are pretty easy.. I grow in HP promix as well and I just did 8 or 12.. The 4 four that didn't make it were older and one was newer. And it's pretty simple.. very little water.. Not a ton of light and if they pop mine almost always grow. Follow along with my grows and see what I do with Hp Pro mix and tap water at 50 ppm. I have good tap water which helps a ton.. Not sure of your water quality.. It's always worth it as a grower to look into your local water quality report if available to you.

Over watered. This kind of cardboard pots are a bit tricky because they retains too much water. You can add holes to the bottom next time, or directly put the seed in the first 1~3L bucket.