I am sorry you used the advice of the Home Depot "experts". Here is a quote from Al Tapla who developed the 5-1-1 mix: I can say that I haven't actually used cedar bark/mulch to grow in, so I can't comment on the practice directly or from actual experience, but I can say that because the tannins, as well as terpenoid and phenolic compounds cedar is rich in are known to be allelopathic (inhibit growth) to many other plants, I have discounted the likelihood that it would be a suitable choice for me. :-(

Thanks Kelley! I'm still on the fence about how well my tree is doing but so far it doesn't look like there's any large infestations or obvious diseases. The only explanations would have to be root rot, lots of fungus gnat larvae, or not enough food for the tree. And I'm hoping it's not the root rot! With your mix, it might be due to the fact that each of those materials hold water very well. From all the research I've looked at online, vermiculite and perlite are usually recommended to be chosen for just one or the other in most soil mixes. Or a mix of both to equal 1 part. The only time I've seen a mix include both as separate parts was IVOrganics on YouTube but I didn't stay updated on how the tree fared. If your vermiculite was a larger, coarser type then it might be ok? I've read vermiculite tends to hold water very well due to absorption while perlite just gets wet on its surface. Is your lime also on that same mix? It probably is just the mix's drainage...I think an expert should give you a more informed opinion on your eureka. I've had my first lemon for only a month now. My advice would probably be to not listen to my advice lol

Thanks for the replies folks. The coating is simply water as we had given it its occasional spraying before the picture there is no signs of any pests or anything of that sort. Do trees require more water once they start bearing fruit? Wonder if the old water schedule of roughly 1 soaking per 2 weeks during winter had become too little after blooming and fruiting... Also from your experience how often and much should we fertilize. We currently do a couple of table spoons of nitrate rich fertilizer every 2 months. we have a keffir lime next do it that is doing wonderful with similar treatment. Is the lemon just more fickle and susceptible to temp and water etc? thanks for your thoughts and advice.

peppystud, there are very many types of lemon trees. However, the two most common in ground planted lemons, by a very wide margin, are either Eureka or Lisbon. I would be very surprised if someone planted a different variety. Dwarf has nothing to do with variety, it has only to do with the type of root stock.