Hello! I am in my first season growing roses from seed and need some advice with an OP seedling of David Austin’s Evelyn rose. Hopefully you guys can advice me before many more germinate with potentially the same issue. They are currently in a coir, sand, vermiculite based potting media.
I have attached a photo showing the cot leaves looking fine, very rich dark green however the first 2 leaves have instantly become more pale and looks like interveinal chlorosis, its a little hard to see on the photo. Can anyone advice if this is actually normal or should I start applying a dilute feed or some other supplement? and if sow how often? Sorry if this is a silly question, but my seedling doesn’t look as healthy as many on this forum and I’d love to know what i’m doing wrong before more seeds germinate.
alexd101, it is also advisable to keep an eye on the pH level of the soil. Ideally, this should be around 6.5 to a maximum of 7.0. The suitable pH-value for Rugosas or Rugosa hybrids is 5.5 to 6.0.
You may wish to try the ‘weakly, weekly’ method. If the liquid food suggests one tablespoon of fertilizer per gallon of water applied every two weeks, use a half tablespoon per gallon every week. As with all fertilizers, water well prior to application to prevent burn. Half strength significantly reduces any potential of harming tender young seedlings and, if you find it insufficient, you can easily add more. I use it for young seedlings and newly propagated cuttings.
From what I’ve seen, chlorosis in a very young seedling can be either environmental or genetic in origin. If you have other seedlings in the same potting medium that look okay, then it could be a genetic problem, although that wouldn’t normally be my first assumption. Often seedlings that have genetic problems will also suddenly cease to produce further leaves, in my experience. If all of your seedlings look like this, then it is more likely to be caused by the medium. That would be my primary guess in your case.
If it’s the medium, the sand is a likely suspect; insufficiently processed coconut coir can also cause trouble, although I haven’t encountered that personally. I don’t know where you are, but I’ve had problems in my area with commercially available sand that seems to contain salt. Almost no amount of rinsing seems to be sufficient to mitigate the problem caused by the use of such sand. Coconut coir can also contain salt, but coir processed for horticultural use should generally be safe. If salt burn has occurred, the only solution is to replant into a clean, low salt mix as soon as possible (maybe soaking the seedling’s roots in plain water briefly first), and in that case I would also not use any fertilizer initially. If the roots are damaged by salt, they will need to be stabilized before any fertilization occurs, or they could be injured further. Fertilizing an already salty medium will only exacerbate the problem, obviously.
If the issue might just be a simple deficiency due to a very nutrient-poor medium or an overly high pH, which is less common to see in such a small seedling, I would also recommend being careful about the frequency of watering and the kind of water being used. Ideally, you won’t apply new water or mild fertilizer solution until the soil has very slightly dried on top, and you might want to avoid using tap water if your pH is very high.
Thanks so much for your insight, I have potted up a couple of newly germinated seeds in a different potting medium that doesn’t have any sand and also has some nutrients included so hopefully that can provide me with some level of comparison. I seem to be getting pretty good germination so far so hopefully issues can be ironed out early.
