My guess is either lack of water, or under fertilization. If they are very new, I doubt it is fertilization. Well draining mixtures may require more frequent watering. Could they be too dry ? Especially young seedlings often have shallow roots and if the mixture drains very well, the top layer of mix will have too little water. This is why you plug grow these seedlings initally to keep the small plugs very well saturated.

I would scoop them out and replant in smaller pots where the drainage is not so fast.

I have them in the smallest pot I have(smaller and shorter than a yogurt container) & have been really careful not to let things get too wet or too dry. So I am pretty sure they are not too dry.

They aren't in a super well draining mixture or anything they have the same thing as all my others (peat & vermiculite). Maybe I need to put them in a sandy mixture?? The thing is this is a hardy native perennial so I wonder if fertilizer is really what it is needing right now?? They wouldn't get fertilizer under wild conditions but then they wouldn't be in a sterile media either. I don't mind if they grow slowly but I don't want to be loosing those leaves.

I can look up the seedling fertilizing levels which I know have been posted on before.

What do folks think? should I try it?? Especially considering these are natives that like lean/nutrient poor soils?? Anyone with experience germinating natives??

Kate,

"They are native plants from the southwest that like good drainage/rocky soil. Their first set of real leaves are turning a bit yellowish & I am concerned... I used sterilized peat moss & vermiculite to plant them in."

Both peat moss and vermiculite are water retentive -- the very opposite of good drainage. These seedlings may be drowning. Also, how strong was that hydrogen peroxide you watered them with? You may have burned the root hairs right off of them.

Normally perlite is added to peat moss to increase the drainage. The perlite retains air, which is the very opposite of vermiculite, which retains water. Vermiculite in a fairly fine form is best used on the surface of a seed-starting medium to keep moisture there to aid germination. Mixing it into peat moss is a questionable practice.

Most professional growing media based on peat moss have some nutrients added, including a significant amount calcium, which is absent from most soluble fertilizers.

If your media does contain just peat moss and vermiculite, it is both sterile and devoid of nutrients. You should water with a one-half strength complete liquid fertilizer that contains a complete complement of trace elements.

Since your growing media is sterile, it doesn't contain the usual population of soil bacteria and other organisms, so you should not use a formula that contains any urea. Unlike in garden soil, the urea won't be converted to nitrates and it will just build up to potentially toxic levels. Also, the ammonia form of nitrogen is bad for some plants, such as pansies and -- who knows -- maybe your Oenothera. So, ideally, your soluble fertilizer should contain nitrogen only in the nitrate form.

"Maybe I need to put them in a sandy mixture??"

I would try that. And weak soluble nutrients. With sand you are essentially using a form of hydroponics, so a hydroponics supply house would be a place to look for suitable nutrient formulations. Since your plants need both phosphate ions and calcium ions and since calcium phosphate is relatively insoluble, you need to alternate feedings of calcium nitrate and a soluble formula containing everything else including the soluble phosphates.

I don't know of a formula that uses chelated calcium (although there may be such a thing) so, as far as I know, no single soluble nutrient formulation is adequate for your sterile growing medium.

When it is said that a native plant prefers lean, nutrient poor soil, that usually means low nitrogen and good drainage, but not no nutrients at all. Including trace elements, all plants need a minimal amount of over 15 different elements, and many element pairs need to appear in a ratio to each other that falls within a particular range, so excesses can be as harmful as shortages.

MM

I thought the sterile medium would help with damping off but maybe I was wrong. I think I can use aquarium fertilizer which is basically just trace minerals with a tiny bit of nitrate to get the trace for a stopgap measure. Then I will use something else for the macronutrients. I will probably just put them in a sandy well draining soil so they can really get going & get some trace elements from the soil as well.

Thank you for taking the time to really address my questions MM.

Kate

Kate, forgive my curiosity, but I am not familiar with the use of H202. I tried to do a search, but all responses were in reference to fish tanks and fountains.If someone could enlighten me, I would be very grateful - all information is gold. Geol.