did you harden them off from the fake indoor light to sunshine.. or just blast them out into full scorching sun ..

think of my pastey white, freckeled red headed boy ... and the first day he runs into the sun before i can slather on sunscreen.. and you might have your answer ... red as a lobster .... thank god he doesnt scorch ...

new growth should be fully accustomed to sunlight.. the old leaves can be removed ..

ken

The top leaves didn't get 'fried'? That doesn't sound like sun scorch, to me. Which, by the way, fragile (un-hardened) leaves can get in much less than 3-4 hours.

No the new leaves that are coming out are fine - it is the lower part which has leaves turning brown - should I spray them with something? Never seen it happen before though...

ritug,

If nothing ever went wrong with our gardening activities, we wouldn't learn anything. I have had the exact same problem you had and, in my case, the problem was nutrient deficiencies. Lower leaves that can't get enough light will also die, especially if the plant wilts for lack of water.

It is best to use a soluble urea-free nutrient formula in a sterile medium like Miracle-Gro Potting Mix, because there are no soil microbes present to break the urea down into usable nitrate and ammonium ions. In the absence of the soil microbes, the urea can accumulate, possibly to harmful levels. Plants can't use urea directly through their roots, although apparently it can be used in a foliar spray.

I used to use the urea-free Peters African Violet food for my indoor plants, but apparently it has been discontinued and I now use Better-Gro Orchid Plus diluted to about one-half teaspoon per gallon. You can get it at several online stores, including Amazon, or if you have a Lowe's Home Store handy, they usually have the Better-Gro products in their garden section. Some garden centers also have it.

You can detect an early onset of nutrient deficiencies by watching the zinnia seed leaves (cotyledons). You can see one "peeking out" in this picture. It is still fairly healthy even though the plant is fairly well advanced.

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As long as the zinnia plant has plenty of nutrients, the seed leaves will remain green and healthy even though the plant has grown considerably. The plant will "steal" nutrients from the seed leaves if it experiences a nutrient shortage, and they will shrivel and die. If the condition persists, the plant will begin stealing nutrients from the lower leaves to feed the newer leaves. My Mother used to refer to that sort of thing as "robbing Peter to pay Paul".

ZM

Thanks Zenman

I think that is what is happening. Would it go away if I plant them outdoors - which is likely to happen in about 10 days. I thought it was the sun scorching the leaves and hence I started keeping them indorrs away from light.

I am hoping once I plant them outside - they will grow fine.

Thanks

ritug,

As rhizo said, it doesn't sound like sunburn if only the lower leaves were affected. I have a bunch of my zinnias still in their pots on the front porch to allow them to get used to the outdoors before I actually place them in the ground. It is a good idea to "harden off" young plants before putting them in the sun. Sunburn looks more like a partial bleaching of the leaves. Apparently some chlorophyll is destroyed. It isn't until several days later that they turn brown. Sometimes they come out of it, if the sunburn isn't too bad. I still suspect a nutritional problem. If your soil is good, planting them outside into the soil should cure the nutritional deficiencies.

ZM