I had this problem outdoors in a new bed I created. I had been watering it with a rain barrel, which previously held common, household strength bleach.

My error was in thinking that bleach was an acid. It's not. It's about a 13 on the pH scale, totally a base. I screwed up the soil conditions & had to apply ammonium sulfate to the entire area. Within 2 weeks I saw improvement & everything has been peachy since May.

I did, mind you, do a soil test first before taking any actions to confirm exactly what the error was. This was my DUH moment of 2010. Neither coffee nor coffee grounds are strong enough to correct this problem.

Although I had washed out the barrel several times, apparently it was possible for enough trace bleach to remain to do damage. Wondering if prior to planting your seedlings if your pots had been washed out with bleach & enough trace remained to do the same kind of harm?
---Laura

The pots were new from the store, I just rinsed them out with water. It's possible they might have gotten laundry detergent or dial antibacterial soap into them since I did the potting in the laundry tub. One of the bags of potting soil may have been mixed wrong since it smelled a little funny, that's why my initial guess was that the problem was caused by too much fertilizer.

Interveinal chlorosis on lower leaves can be magnesium deficiency, sometimes caused by high pH or excessive calcium. It makes a distinctive "Christmas tree" pattern.

Don't use coffee, caffeine is phytotoxic. Used grounds are OK. Neither is going to have much effect on pH.

Here is a link that might be useful: Scroll down to magnesium

In my limited experience with rugosa cuttings, they very much want a winter dormant period. Since they are very tiny their first winter, this can get tricky.

Aside from that, it sounds like overwatering. The off potting soil could be much more water retentive, and the bottom of the pot is a swamp after the top has dried out.

Well, I ended up getting some HollyTone because it was the only thing that was an acidifier and contained magnesium. It probably also contains some counter-productive stuff like more fertilizer though. Anyway, now I'll wait a week or so and see if there's any improvement. If not, I guess I won't have any choice left but to plant them outside.

You might have spider mites. The next time it is time to water them, take them outside and if you can quirt water on the underside of the leaves real good. My seedlings get yellow leaves too at the bottom, I just take them off and new ones always grow in their place, are they close and touching the soil? If so take them off, you really don't want any bottom leaves touching the soil.

Also I do want to mention that you do want to get rid of the fungus gnats, the larvae from them eats the roots. I spray the top of the soil with Bayer Insect Spray lightly, and only once should take care of the problem.

Ugh. So today I inspect my roses, hoping that they will look a bit less yellow; instead I find that the hollytone has sprouted big clouds of white mold. I can't have that in my house, getting blown throughout the rest of the house by the air conditioning. I had already been considering if there was any way I could spray them without getting nasty chemicals in my house. So I decided, the heck with it - I hauled all 20 or so pots out in the back yard, put on my gloves and mask, mixed up a batch of the heavy duty rose and grape spray, and did the pots and all the other plants in the yard that needed it.

I'll have to leave the pots out there for a few days for the chemicals to subside before I let them back in the house. I hope the wind doesn't knock them over, and if it starts raining I'll have to quick move them to the porch. Meanwhile I have to think of a way to kill off any remaining fungus gnats in the basement so they don't just reinfect the pots.

Did you check first to see if the soil is too wet beneath the surface?

And, I wouldn't dream of using a dry organic fertilizer indoors.

Have you considered watering all the time with a half strength water soluble fertilizer. If you need to make the soil more acid, use something like Miracid. Water solubles are readily absorbed by the plants and don't require the nutrients be broken down by soil organisms like an organic fertilizer. Although they stink, well diluted alfalfa tea or fish emulsion would also make great tonics for your indoor plants. Any of the above would help green up your plants quickly unless there's a soil deficency
I tried growing rooted cuttings indoors under lights one year, but after fighting mildew and white flies I decided not to anymore.