I didn't order chlorosis. So why do I have it?

Hi, folks,

Odd thing… apart from the little excursion into mildew,the seedlings seemed to be doing fine. Then just suddenly, a few days ago, several of them seemed to start growing very yellow leaves. There was no recent repotting, and they’re of various lineages, so it isn’t something genetic (I think). This is the second year (not in a row) I’ve had this happen. Am I doing something wrong? The seedlings are planted in a mix of equal parts potting soil, peat moss and vermiculite.

Surely they wouldn’t have spider mites, would they? If not, maybe they’re hungry, Fara. It wouldn’t hurt to give them a little very dilute food.

Try checking the pH.

Not just the pH of the soil, but the pH of the water they’re getting.

In my limited experience I had chlorosis on certain seedlings from crosses involving Canadian roses x portland damasks. They were potted in a soiless medium, and there was yellowing between the veins of the leaves. The symptoms went away as soon as I transplanted them into rich organic soil taken from the garden.

Some crosses are much more inclined to chlorosis than others, but you may want to monitor soil moisture levels as well. Small seedlings are very prone to root loss when young and excess soil moisture can make that an issue. I water very sparingly when seedlings are small.

Paul

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Thanks for the tips, everyone! I’ll look into them all and see what helps!

When I was starting with rose seed, I just grew OP seed to try to get the hang of it. I had really bad chlorosis, and it actually killed some seedlings. I was using small pots and a commercial seed-starting mix that had always worked well with some other types of plants.

I talked to other people and experienced, and discovered that my water was alkaline and that many, if not most, packaged seed mixes contain lime to counteract the acidity of the peat moss. I found larger pots were less vulnerable. I also saw a difference in response: R. rugosa was the worst, by far. I was able to save a lot of the seedlings by using an acid fertilizer and iron chelate. It was years before I dared use really small pots again, and I have made my own mix since then. I still can see chlorosis in plants that have gone without repotting for a long time.

Iron chelate can be a challenge to find, but it is worth the search. I use the powdered kind you suspend in water and water the pot with. I initially didn

Rugosa seedlings can be grown quite happily in a soil mix that is nearly 100% sand, as long as you add some nutrients occasionally. Their native soil conditions are coastal sand dunes and they like this just fine. Normally their roots would never encounter peat moss and this is a major ingredient of most potting/seed mixes.

Roger,

I’ve got iron chelate, and that seems to be helping. I did test my soil and it is rather basic, so I’m going out later to get some soil conditioners.

Paul,

Maybe that’s why rugosas just won’t grow for me. I’ve been meaning to move them to new beds, maybe I should put in a special sandy bed just for them. Hmmm…

add mag sulphate (epsom salts) from drugstore or garden ctr. at rate of 1tsp per gallon and good quality chelated iron powder with 1 half tsp per gallon water with half tsp dish detergent. drench once per ten days. this will give good color change. do three weeks in row. then give a break. any product with kelp is wonderfull periodically as well for overall health. chelation of iron is key to sustained good results. gjg

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