Fertilizer and temperature

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Fertilizer and temperature
mark akimoff via pbs (Mon, 06 Mar 2023 10:02:49 PST)

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

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