• Dear Guest,

    We've been using a forum format called vBulletin for over seven years and the program is no longer being developed, so that means no more updates or security patches. vBulletin has never been compatible with search engine optimization and it does not support the multitude of various devices most people use to access the internet, so it's time to say goodbye to vBulletin.

    For these reasons we have moved our forum to a new format that will support and encourage growth for the next generation of grower and DIY tobacco users.

    So please post any issues you're having with using the new site.

    As usual, you may login with your old password.

Northwood seeds

Last and First Frost Date - When Is It, Really?

Joined
Sep 1, 2014
Messages
3,010
Likes
446
Points
83
Location
Edmonton, AB, CA
#41
I don't have to much concern about when I transplant. I've never had frost damage anything I have covered. When I plant my veggies changes every year depending on long term forecasts. What I would like to know however, is simply how much time before transplanting should be given for indoors growing? Is longer better?
 

Smokin Harley

Well-Known Member
Joined
Aug 25, 2014
Messages
2,573
Likes
99
Points
48
Location
Grant ,Alabama
#42
yes , those first /last dates are only averages over a long period study . Farmers Almanac is probably just as good or better . Microclimates have to be considered also. One year I had my whole garden out by the weekend memorial day and the very next year I got frozen out and couldnt get it all back in until almost 2nd week of June. Our avg last frost is May 15
 

deluxestogie

Administrator
Joined
May 25, 2011
Messages
12,548
Likes
1,390
Points
113
Location
near Blacksburg, VA
#44
Here's a quickie map of first and last freeze dates from Bonnieplants: https://bonnieplants.com/library/first-and-last-frost-dates/

As for using the Old Farmer's Almanac (OFA), it's seasonal weather predictions utilize the most recent 30 year running averages derived from NOAA data. It's more accurate than a groundhog, the calendar, the moon or the vernal equinox. On the other hand, OFA monthly temperature and precipitation forecasts (expressed, like the NOAA data, as above or below average) is correct about 50% of the time. So, for that finer-grained forecasting, it's comparable to reading animal entrails. Use your local meteorologists for that.

For first and last frost dates by ZIP code (in the US), the Dave's Garden site is still the handiest: http://davesgarden.com/guides/freeze-frost-dates/index.php?

...but these are statistics. They have no say on individual events.

Bob
 

Smokin Harley

Well-Known Member
Joined
Aug 25, 2014
Messages
2,573
Likes
99
Points
48
Location
Grant ,Alabama
#45
hah, I read the Farmers Almanac for this winter and it was dead wrong. I'll still go by seed planting cold crops about Easter and the rest goes in Memorial day weekend,unless it happens to be raining which it most likely does, then I shoot for the first weekend in June.
 

deluxestogie

Administrator
Joined
May 25, 2011
Messages
12,548
Likes
1,390
Points
113
Location
near Blacksburg, VA
#46
Easter is always the 1st Sunday after the 1st full moon on or after the vernal equinox. So it moves around. Passover always starts on the first full moon after the vernal equinox, unless there is an intercalary (leap) month (in the Hebrew calendar) which falls after the 1st full moon after the vernal equinox, in which case Passover starts on the night of the 2nd full moon. What is most curious is that they both represent the date of the Passover holiday (i.e. the Last Supper) celebrated in ancient Judea, but are now jiggled by differing calendar innovations. Nonetheless, both are based on the combination of solar and lunar cycles.

My point is that neither is particularly reliable as a date of agronomic significance.

Bob
 

CoralReefs

Suburban baccy farmer
Joined
Apr 1, 2012
Messages
235
Likes
13
Points
0
Location
Central California
#47
Always found the whole "First Sunday after the first full moon after the spring equinox" to be a rather interesting way to choose the date to observe a non-nature oriented holiday.

Anyway, hi all- long time no see!
 

CoralReefs

Suburban baccy farmer
Joined
Apr 1, 2012
Messages
235
Likes
13
Points
0
Location
Central California
#49
So far , nothing. I have not decided whether I am growing baccy this year or not. I have had my hands pretty full with work lately. My hobby time has been pretty minimal.
 
Joined
Sep 1, 2014
Messages
3,010
Likes
446
Points
83
Location
Edmonton, AB, CA
#50
We get so excited about last frost. True, it's a great indicator of when you can start planting, especially seed, but I don't think it's so crucial to get tobacco plants in just as soon as you can. Soil temperature is the ultimate decider. If the soil is below 50F, it's kinda pointless to plant outdoors in the ground. At least, according to this study: http://www.nrcresearchpress.com/doi/abs/10.4141/cjps60-038
 

deluxestogie

Administrator
Joined
May 25, 2011
Messages
12,548
Likes
1,390
Points
113
Location
near Blacksburg, VA
#51
China, I'm not sure what to make of that 1957 study that you linked. The plants were grown entirely at the specified soil temps throughout their growth to maturity--which is not likely outdoors. In addition, they were grown in 1 gallon pots, in a greenhouse, between late October and late November (in Canada), and supplemented with artificial light. All pretty atypical growing conditions.

I agree that trying to grow them in winter, even without freezing, is pointless. But when they are transplanted outdoors in cool weather, they are likely to experience increasing average temp as each day passes. Since the plants are most vulnerable to pests when still very small, warmer soil temps would reduce that period. On the other hand, some tobacco pests are totally absent during the early season.

Bob
 
Joined
Sep 1, 2014
Messages
3,010
Likes
446
Points
83
Location
Edmonton, AB, CA
#52
China, I'm not sure what to make of that 1957 study that you linked. The plants were grown entirely at the specified soil temps throughout their growth to maturity--which is not likely outdoors. In addition, they were grown in 1 gallon pots, in a greenhouse, between late October and late November (in Canada), and supplemented with artificial light. All pretty atypical growing conditions.

I agree that trying to grow them in winter, even without freezing, is pointless. But when they are transplanted outdoors in cool weather, they are likely to experience increasing average temp as each day passes. Since the plants are most vulnerable to pests when still very small, warmer soil temps would reduce that period. On the other hand, some tobacco pests are totally absent during the early season.

Bob
They controlled possible confounding variables by making pots, soil, and light the same between conditions so they could more legitimately attribute temperature to growth rate. Although the study lacks real life validity due to the fact soil temperature isn't constant, I think they did a good job of taking the question of how tobacco grows vs soil temperature beyond the anecdotal.

I think it's safe to say from these results that so long as my plants have space for roots to expand, remaining in the pot a little longer while the garden warms up can't hurt.
 

deluxestogie

Administrator
Joined
May 25, 2011
Messages
12,548
Likes
1,390
Points
113
Location
near Blacksburg, VA
#53
Will a plant alter its pattern of root growth, in response to soil temp? I don't know the answer. But a 1 gallon pot certainly constricts normal root growth. Does a tobacco plant's growth pattern at a given constant soil temperature depend on the angle of the sun (season of the year)?

Tobacco is a perennial, and as such, its growth patterns vary through the changing seasons, when grown indoors.

I guess I'm just not comfortable that the tidy experimental constraints of the 1957 study did not introduce confounding factors that render their conclusions uncertain.

Bob

EDIT: One other peculiarity of the study is their method of maintaining the designated temperatures of the potted soil. The temperature of the pots was maintained by a controlled water bath, but they also added thermal insulation to the surface of the soil--a layer of styrofoam beads. We know from other studies that all plant roots respond to sunlight on the soil. Light actually penetrates several inches into the soil, which is just where tobacco roots grow. https://www.amazon.com/What-Plant-Knows-Field-Senses/dp/0374533881/
 
Top