Germanation questions

[GpsFrontier]

Hello Rye,

Question. I've read here the rock wool isn't supposed to sit in water, clearly my first mistake. I can fix that tonight, and let drain/dry. Does the wool not dry out and fail to provided the needed moisture to the plant?

If rockwool sits in water it sucks up so much water it suffocates the roots. Eventually it would completely dry out if allowed to drain forever. But depending on heat and humidity, that could take from 24 hours to a week. So it's not like it would happen right away. I don't really like using rock wool, but I attached some pictures of a easy seedling starter I made for the rockwool cubes. It's just a Tupperware container I cleaned out, and cut openings in the lid to hold the rockwool cubes. I put a little water/diluted nutrient solution in it, and I just sloshed the water inside so it wet the bottoms of the rockwool cubes once or twice a day as needed. With the lid on the humidity inside kept the roots hanging out of the cubes from drying out to much.

Personally, I prefer to use coco fiber. It's cheap, easy to use, and holds moisture well without suffocating the roots. I also attached some pictures of how I start seed using coco fiber. I simply use two Tupperware container's the same size so one fits snugly inside the other. I like using short ones for this so you don't have to fill tall ones with coco fiber, their just seedlings and it doesn't need to be deep. I use a cheap handheld soldering iron to make/burn a lot of holes all over the bottom, and part way up the side. You can make the holes any way you want, but I find the soldering iron the easiest and fastest.

Then just like you would with potting soil, simply fill the container with the holes on the bottom with coco fiber about 3/4 the way. Put your seeds in, then top off with a layer of more coco fiber to cover the seeds to whatever depth it calls for on the seed package. I usually just use between 1/2 and 3/4 inch. Don't pack down the top layer of coco fiber, it will softly settle on it's own. Just make sure your coco fiber is already wet before you start, or it will float and take forever to absorb.

Once you have your seeds ready, fill the other Tupperware container without the holes with plain water. Place the container with the seeds inside the one with the water and let the coco saturate with water for a few minutes. You can do this outside or in the sink so if some spills out it wont make a mess. After a few minutes of soaking take the container with the seeds out and dump the rest of the water out of the other one. Then set the container with the coco and seeds on edge so it's tilted so it drains quickly. Let it drain for 2 to 3 minutes. You can do that outside or in the bottom container. Now you can place the coco and seed container in the bottom one. You don't need to, but it will keep it from dripping and making a mess if you keep it in the house.

I water them like this once or twice a day as needed. Once the seeds sprout and pop up through the coco fiber, you can start watering them with diluted (1/10 to 1/3 strength) nutrient solution. I make one gallon of full strength nutrient solution. Then to make the diluted nutrient solution, I just pour a little full strength nutrient solution in (about 25%), and the rest (about 75%) plain water. Instead of just dumping out the leftover after you water, you can save the diluted nutrient solution in a container to use next time. Just to make sure to keep it covered and in a cool dark place between watering.

Second, when I set the rockwool into the baskets I am supposed to bring the water up to the bottom of the basket just touching the rockwool, or do I fill to 1/2" under the basket and let the roots reach down to it?

This is a common question most beginners using a water culture systems have. So I went into detail about it on this page: Water Culture Systems, just scroll down to the section titled "Should the water level be above or below the baskets?"

P.S. The Kratky method is really nothing more than a standard water culture system without the air pump. I also go into detail about the pro's and cons of the the Kratky method right under the section about the water level.