JDelage wrote:All - I have 10 seedlings: 2 cucumbers, 2 peppers, and 6 tomatoes. I started them together (which probably was too early for the cucumbers). The seedlings are doing OK, some better than others. The tomatoes are more advanced than the peppers, and the cucs dwarf everything else. The tomatoes are in 3 inch square plastic pots, the 2 cucumbers in recycled family size yoghurt containers. They are in a mix of coco coir, purchased compost, and homemade worm castings. They are under an LED grow light with a light fan on.
My question are:
1) How often should I water them? I understand I should water them from the bottom, but at what frequency?
2) Should I lower the water's pH to 5.5 - 6 before watering them?
3) Should I had liquid nutrient to the water and what composition?
Watering little seedlings is the trickiest part as they are very sensitive to both under and over watering. Your potting mix sounds a bit heavy and moisture holding, which will make it even harder. It would have helped to have some mineral element in it to help with drainage and lighten it up, like perlite. So put water in the bottom of the tray, just enough to touch the bottom of the soil. Leave it for a couple/few hours and then dump (or suck out with turkey baster) any excess. For me with little seedlings under lights, I do that every day. If the surface of the soil is getting dry and crusty give them a little more water. If they are on a heat mat, they dry out faster and may need twice a day watering. You are aiming for consistently just damp. If you can touch the soil surface lightly and press water out= too wet.
I think it helps to let your water sit over night to evaporate the chlorine out (if you are using tap water). I have never worried about changing the pH. Neutral is fine. If your water were alkaline, you would want to correct that.
If you have compost and worm castings, that may be sufficient, especially when they are little. Your plants will tell you if they are not getting enough nutrients. They will get yellowish or not dark green, slower growing, not very leafy. If you see this, add some nutrients.