To Arnold, I had the same issue with some winter growing South African's bulbs, like Watsonia/Ferraria/Moraea, browning/crisping of the leaf margins in cold soils. Switching out to the Dark Weather formula solved the problem and I have much more robust plants growing through the cold winter conditions we see in my unheated greenhouse (Western Oregon, 620' elevation). To Jane, once it warms up,and I feel we are safely past the very cold nights, I'll switch to a bloom based formula as well, with some phosphorus in it. Looks to be sometime in April before we might get that? I have never added a CAl-Pril type of product, mostly because I have always used a liquid feed with CA/Mg. I did have my standard potting soil for bulbs mix tested at a Portland lab and it was interesting to see the results. I think the test was about $40 and gives a good baseline for what type of nutrition is present. If I can find the lab report maybe i'll share it up on the forum. I'm also using a VAM-Water soluble mychorrhizae this year after reading some interesting studies on Crocus sativus bulb offset increasing related to VAM. Best, Mark On Mon, Mar 6, 2023 at 9:35 AM Jane McGary via pbs < pbs@lists.pacificbulbsociety.net> wrote: > Glad to get responses from the professionals! I use "non-organic" > fertilizer because it is convenient and does not attract animals the way > bone meal and fish fertilizer do. I don't have access to products sold > to the nursery industry, but the Dark Weather Feed Mark mentions sounds > very desirable for the range of bulbs I have, which are almost all > winter-growing. For years I've been using Miracle-Gro Root and Bloom, a > lower nitrogen formulation, at half strength and just 2 applications a > year. As Robin recommends, the bulbs that are in pots (some are directly > planted in a raised bed) are repotted frequently; I used to do it every > other year, but mixing the soil has become physically challenging enough > that I've fallen to every third year. I haven't added calcium to the mix > but it contains a lot of ground white pumice, which has a higher pH than > some other available components. Perhaps I should add Cal-Pril, a > slow-release calcium product. > > We may be getting daytime temps into the 50s F in another week or so, > and I have the barrel of rainwater ready to mix fertilizer then. > > Jane McGary, Portland, Oregon, USA > > > On 3/5/2023 6:47 PM, Mark Akimoff via pbs wrote: > > I have had this dilemma more than a few times over the past few years. > The ammoniacal nitrogen form often messes with the pH in cold weather > sometimes dropping it significantly, and at low temps the ammonia won’t > nitrify and can cause toxicity. Using a nitrate form is better in the cold > weather, in the greenhouse many of the bulbs are starting into very active > growth now and do need some feeding. I recently discovered a product > called Peters Dark Weather feed, it’s a 15-0-15 with cal mag and micros > that is mostly nitrate nitrogen. I have been doing 50 ppm which is a pretty > low dose but the plants have responded very well and I’ve even seen a few > nutrient deficiencies corrected despite the temps in the 40’s. > > > > Mark > > > > Illahe Rare Plants > > Salem, Oregon > > > > > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… > Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> > PBS Forum latest: > https://pacificbulbsociety.org/pbsforum/index.php/… > _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> PBS Forum https://…