Re: HYB: weather, germination

Linda -- Your message just prompted me to step out and water the seed pots, since we've been about a week without rain. I think the keys to optimum germination in outdoor planting in pots are (1) continued moisture of the potting medium and (2) sufficient mulch to keep the seeds from erupting, while not preventing the soil from "breathing". This is why I favor an inch of pine straw as the mulch cover. (For those not familiar with the term, "pine straw" means the long needles of a fir like white pine, which make an airy interwoven fabric over the pot but don't mat down.) It is also why I don't favor leaves, which do mat down. The pine straw mulch filters the rain or other watering, so that it doesn't cause the seeds to surface, and provides constant shade that tends to moderate extremes of freezing and thawing that also would cause seeds to erupt. The pots sit on the ground in a wooden frame covered with plastic chicken "wire" to keep out the squirrels. It is in full sun. Once the sprouts have started, I think the best insurance against damping off is good drainage and depth of soil in the pots. The 1-gallon growers' pots I am using are 7 inches deep, which means that the seeds have 6 inches' depth in which to sink their roots, and plenty of room for excess moisture to drain off. In years past, I used little aluminum loaf pans only 2 inches deep and got very good germination, but the roots were thin and stringy, intertwined with their neighbors and not healthy enough to withstand a season of excess rainfall either in the pots or after planting out, as I learned disastrously a few seasons ago, after many years of being lucky. In contrast, it's a joy to see those strong, healthy roots stretching down toward the bottom of the pots I am now using. Still, with all of the above said, I think, as I have said in an earlier post, that there is a genetic code in the seeds that determines the overall rate of germination in any given year's crop. -- Griff

----- Original Message ----- From: "Linda Mann" <lmann@volfirst.net>
To: "iris- talk" <iris@hort.net>
Sent: Tuesday, January 10, 2006 6:25 AM
Subject: [iris] HYB: weather, germination


This is the kind of winter that was giving me less than 5% germination
planting seeds outdoors, motivating me to find another way.

Seeds got a lot of chilling in December - temperatures down to 12oF for
about a week, well below freezing most of the month.  Starting a few
days ago and for the rest of the week, lows will be in the 40s, highs in
the upper 50s & 60s, light showers off and on - perfect  germination
weather.  I found one seedling already up about an inch yesterday.

January typically has the coldest temperatures of the winter - most
seedlings that germinate outdoors this early are likely to be killed,
especially if temperatures do the usual and drop abruptly to the teens
again.

This is when the strategy of taking either a 3 month long or two
separate chilling cycles before germination is a good plan for a seed!
I'm afraid all those easy to germinate seeds that don't need chilling
and that didn't get burrito'd are done for.

--
Linda Mann east Tennessee USA zone 7/8
East Tennessee Iris Society <http://www.korrnet.org/etis>
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