Mosca- Frosted Guava

Yes, I water wide and deep and until run off from seedling to harvest and have been doing so for the last 35+ years without any dramas. Your plants roots will want to grow deep, they can not do this if only the top soil is moistened with small amounts of water. Just remember to let the top 1 to 2 inches to dry out before watering wide and deep to run off again. Deep watering, apart from encouraging root growth, also helps to prevent any nutrient salts from building up in the soil to toxic levels. As your soil mix looks well draining, I say "go for it", your soil will not grow germs and your plants will not drown and die! Cheers, Organoman.

I water at least the plant's size beyond the plant. So, if your plant is about 10cm across I water underneath the plant and the area about 10cm beyond the plant. So for a little sprout I'll be watering an area the size of a soda can. Then with a plant your size I'm watering an area the size of a saucer (15cm). Lifting your pot is also a good habit. As you get to know the weight it becomes easy to tell how much moisture is hiding inside your pots. So, if you're ever on the line wondering if they need more water you can lift the pot. If it's light you know you should water but if it's still heavy even though the surface is dry you'll know you should hold off on more water.

No, your pots are huge and the plants are still seedlings. So much moisture will probably kill them or at very least greatly slow down the growth. I am not very experienced so I can't really help with how to check nutrient levels, but you're gonna drown your ladies if you water them more than a small cup of water. Also if the drainage is not great, you can get some nasty stuff growing in your soil such as germs.