Jane, In my experience, also in the Pacific Northwest, non-synthetic fertilizers are made available to plants according to temperature and moisture. Higher temperatures increase soil microbial activity, which break down the fertilizer into plant-available nutrients. It's the old adage - "Feed the soil". Being organic, and less soluble than synthetics, the fertilizers will remain in the soil longer, until they are broken down into the nutrients that *can* be utilized by the plants. Particularly in your case, in your covered bulb bed, the fertilizer will not be as susceptible to leaching (from rain) and will remain available to plants for a longer period, i.e., now and continuing as temperatures rise, as the organic fertilizer is broken down by microbes at a (slower) rate that is more thoroughly utilized by the plants over time, or am I repeating myself? This applies to organic based fertilizers. Synthetic fertilizers, which are manufactured from fossil fuels, are more of a "quick fix" -- they are effective in being utilized by plants at a quicker/sooner rate than organics, but they are more susceptible to being washed (leached) through the soil before they can be taken up by the plants, especially in sandy soil, and rainy climates, and they do nothing to contribute to the health of the soil. This is just my two cents regarding fertilizer and temperature. I feel like an acolyte talking to a priestess. Regards, Mike On Sun, Mar 5, 2023 at 4:51 PM Jane McGary via pbs < pbs@lists.pacificbulbsociety.net> wrote: > I usually apply soluble fertilizer to plants in my unheated bulb house > now. However, we are having an unusually cold late winter: near freezing > every night, and in the 40s F daytime. Many plants are in active growth, > if a bit later than usual. Should I apply fertilizer now, or wait until > the daytime temperatures are a bit higher? I don't use pelleted > fertilizer on the container plants but have some for the garden which is > designed to release slowly at cool temperatures, unlike Osmocote-type > slow-release fertilizers which need higher soil temperatures than is > typical in the Pacific Northwest. > The continuing cold is also probably impeding the seed harvest for this > year. I'm told that cold temperatures retard the development of pollen > tubes leading to the ovaries. However, I don't like the idea of bringing > flowering plants into indoor temperature just to encourage seed set, > because I think it would make them go into premature dormancy, which > might limit their vigor in the future. I've always preferred to grow my > container plants as hard as they will tolerate, so that they appear in > character (more like they do in nature). Many of the bulbs I grow come > from mountainous or steppe areas where night temperature is sharply > lower than daytime. > Jane McGary > Portland, Oregon, usa > _______________________________________________ > 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://…