Hi Doc,
I got my seed starter plugs from HTGSupply.com.  I planted seeds yesterday and am wondering if the material that the plugs are made from (compressed tree bark) will provide adequate nutrients for the seedlings (complementing the seedlings' own energy store already inside them) for the first few weeks and until I transplant into a larger container. I have them under FL lights and am lightly watering with spring water for now.

I really enjoy the starter plugs, they are more earth friendly than rockwool, but are just as versatile. I highly recommend them. I even put them in my compost after I use them.  I do not like the jump up starter plugs that expand, they are very messy but the one's made of tree bark with the preformed hole (link); I do like.  There may be some nutrients in the plugs, but I'd use a diluted fertilizer. If the plugs are made from coco coir it is usually recommended you use a high magnesium (Mg) and calcium (Ca) fertilizer like 'Calpex' -see picture.  I have used these 'Organicare' fertilizers with all mediums and seedlings and I have good results.  After I put a seed in each hole, I water the plugs or soil with a diluted 1/3 - 1/2 the recommended amount of fertilizer. I use this fertilizer mix until the plants start to grow rapidly, then I use the regular recommended amount of fertilizer per gallon.

For seedlings and young plants, use a fertilizer that is higher in the first number (nitrogen) like Fox Farm's Grow Big, but you want a good all around fertilizer with NPK and trace minerals too for young plants so that they have all the nutrients they need.  I use the "Nitrex" - see picture - to supliment other fertilizers.  I supliment because, 'Nitrex' only is 6-0-0, and I think you should always give your plants some potassium every time you fertilize.

A good way to tell if your plants need nutrients is to see if the cotyledons (The first leaves you see) stay green or turn yellow. If they turn yellow, you need more nutrients, or light etc. If your fluorescent light is close to the plants, yellowing will be due to lack of nutrients. If your cotyledons stay green, you plant does not need more nutrients.

Good growing,
Dr. E.R. Myers

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