mwaller
Well-Known Member
How do you decide when to plant your seedlings in the garden? Is there a minimum "low" temperature you want? If so, what is it? We're still in the mid 40's at night here in the Seattle area.
Outdoor temperature for planting?
- Thread starter mwaller
- Start date
- Status
mwaller
Well-Known Member
For what it's worth, my seedlings look like this today:
![IMG_20170421_083759953[1].jpg](https://fairtradetobacco.com/data/attachments/16/16838-50e575074a5427972b8721ef8bb8bc18.jpg "IMG_20170421_083759953[1].jpg")
If you'll enter your general location into your profile, it will appear beside each of your posts, and questions about growing will be easier to answer.
SHORT ANSWER: avoid a freeze after setting out transplants.
TOOLS FOR DECIDING:
SHORT ANSWER: avoid a freeze after setting out transplants.
TOOLS FOR DECIDING:
- NOAA monthly temp/precip forecast (live updated), for general expectation: http://fairtradetobacco.com/threads/2225-NOAA-Temp-amp-Precip-Forecasts-Updated-Monthly
- Predicted last frost date, by Zipcode: http://fairtradetobacco.com/threads/781-Last-and-First-Frost-Date-When-Is-It-Really
- As my "last frost" date approaches, I go to the weather underground site and run a temp prediction model for the next 2 weeks: https://www.wunderground.com/
First, enter your Zipcode. The graph gives you ~10 days of info for your specific location. Just above the little radar map, click Wundermap. On the right is a menu of functions. (Dismiss the ad that blocks part of the menu.)
Clear everything, then select Model Data. For the model data, select GFS, then in the dropdown, select 2mAG (which will show temp 2 meters above ground).
Beneath the map, click the video run button. The model will advance step by step, and you can pause it to view a specific map better. The date and time are shown just above the video controls. The double arrows allow advance or reverse by a single frame. This gives you a forecast for 14 days.
mwaller
Well-Known Member
Thanks, Bob. It's been rainy and cool around these parts for quite a while, though today is an exception. It looks like things start to clear up a bit after the first week in May. Perhaps that would a good time...
We are almost certainly in a frost-free time period, but I'm guessing the plants will do better for another week or two indoors with artificial light.
We are almost certainly in a frost-free time period, but I'm guessing the plants will do better for another week or two indoors with artificial light.
greenmonster714
Well-Known Member
Bob: great info
mwaller: I've had my plants outdoor for a while now. A few nights it did dip into the low 40's and they did just fine. I'd say by 5/1 I should be planting some in the garden. Spring seems to have come early for us down south.
mwaller: I've had my plants outdoor for a while now. A few nights it did dip into the low 40's and they did just fine. I'd say by 5/1 I should be planting some in the garden. Spring seems to have come early for us down south.
Equally important is soil temperature. If you plant in a cold ground, your plants will stall leaving them susceptible to pests and disease. Optimal soil temperature is 72F.
Planting in proper soil temperatures will also produce a better yield.
Planting in proper soil temperatures will also produce a better yield.
Smokin Harley
Well-Known Member
Look at your zone for last expected frost date then wait another week , maybe 2 just in case you get the out of left field surprise frost. Your plants should have at least 4 sets of true leaves .I like to set my plants out when they are about 4 inches tall. Tobacco is pretty hardy . It can take some low temperatures once it gets established just not a hard frost..
Thank you Bob, great tool to check the weather ! Thank you for the explanations about what option to use !
I second FmGrowit's post about soil temperature being important. This year I'll wait a bit longer. Even if there's no frost, the temperatures here currently hover between 35F and 55F. I have some seedlings outside under a glass roof, the ones protected by an additional cover and taken in at night are visibly bigger and, I'm sure, will take off much faster once they get transplanted.
If it's too cold, growth is just stagnating (sometimes there's a trade off between this and oversized seedlings suffering in small pots, but clipping the leaves solves that problem up to a certain extend).
I think as well your seedlings are still a bit small, I would wait until they have 6-8 leaves. Space in your box is not too tight yet. Some years ago I started seeds in February in hope of an early harvest, so the summer temperatures would assist better curing. It worked to some degree, but for the seedlings in the field it was a bit early. Until the beginning of June they did not grow at all, but got eaten by slugs and burned by the sun. They eventually came around and gave a fine harvest later that summer. But the plants in warmer garden beds and containers did much better to start with (Pictures). Also, some varieties are probably less sensitive / more weed-like than others.
I still plant some new varieties a bit early in a sunny spot in large pots. They can be covered if there's a late frost, and the slug pressure is much lower. In June I can then already figure out how they cure best. And no matter the general weather development, a certain harvest is almost guaranteed.
If it's too cold, growth is just stagnating (sometimes there's a trade off between this and oversized seedlings suffering in small pots, but clipping the leaves solves that problem up to a certain extend).
I think as well your seedlings are still a bit small, I would wait until they have 6-8 leaves. Space in your box is not too tight yet. Some years ago I started seeds in February in hope of an early harvest, so the summer temperatures would assist better curing. It worked to some degree, but for the seedlings in the field it was a bit early. Until the beginning of June they did not grow at all, but got eaten by slugs and burned by the sun. They eventually came around and gave a fine harvest later that summer. But the plants in warmer garden beds and containers did much better to start with (Pictures). Also, some varieties are probably less sensitive / more weed-like than others.
I still plant some new varieties a bit early in a sunny spot in large pots. They can be covered if there's a late frost, and the slug pressure is much lower. In June I can then already figure out how they cure best. And no matter the general weather development, a certain harvest is almost guaranteed.
ChinaVoodoo
Moderator
From a study on soil temperature and growth of tobacco:
http://www.nrcresearchpress.com/doi/abs/10.4141/cjps60-038
Soil temperatures of 72F seem to be ideal, rather than merely a minimum. 85F results in smaller plants than 72F does. 59F seems like it's at the lower end for growth, while there's no growth at 46F.
These are the actual temperatures in the tobacco growing regions in Canada:
They are planting before the soil reaches an ideal temperature with decent results. Canada produces over 30,000 tons a year.
http://www.nrcresearchpress.com/doi/abs/10.4141/cjps60-038
Soil temperatures of 72F seem to be ideal, rather than merely a minimum. 85F results in smaller plants than 72F does. 59F seems like it's at the lower end for growth, while there's no growth at 46F.
These are the actual temperatures in the tobacco growing regions in Canada:
They are planting before the soil reaches an ideal temperature with decent results. Canada produces over 30,000 tons a year.
CV, This looks like the familiar study of constant soil temperature, maintained by water bath, inside a greenhouse, and with styrofoam beads covering the soil.
I suppose one could generalize from it that plants don't grow well is really cold or really hot sandy loam (what they used), when the temp is maintained without fluctuation for the duration of a potted grow.
At least in my garden, soil temperature swings wildly throughout each day, as well as from day to day and week to week. My tobacco just has to make do. If you've got the data on your soil temperature, and an encouraging weather forecast, AND a sufficiently long growing season, then you can pick the transplant date nearest to perfection.
Bob
I suppose one could generalize from it that plants don't grow well is really cold or really hot sandy loam (what they used), when the temp is maintained without fluctuation for the duration of a potted grow.
At least in my garden, soil temperature swings wildly throughout each day, as well as from day to day and week to week. My tobacco just has to make do. If you've got the data on your soil temperature, and an encouraging weather forecast, AND a sufficiently long growing season, then you can pick the transplant date nearest to perfection.
Bob
ChinaVoodoo
Moderator
This entire topic is pointless for most of the growers in this forum because you can guarantee if you live in a tobacco growing region that your soil will be warm enough.
I think it matters for me. I got interested in soil temperature years ago because it was a dominating factor in whether morels would even come up in a given year. I understand this study is highly experimental and lacks ecological validity. Soil temperature in the real world is not static like you say. However, soil temperature doesn't swing wildly 4" down. In southern Ontario they're seeing a gradual ten degree shift over two entire months. I've dug two feet into my compost in mid June to find a block of ice.
I'm going to plant in hills and raise the albido with a thin half inch layer black mulch to warm it up.
I think it matters for me. I got interested in soil temperature years ago because it was a dominating factor in whether morels would even come up in a given year. I understand this study is highly experimental and lacks ecological validity. Soil temperature in the real world is not static like you say. However, soil temperature doesn't swing wildly 4" down. In southern Ontario they're seeing a gradual ten degree shift over two entire months. I've dug two feet into my compost in mid June to find a block of ice.
I'm going to plant in hills and raise the albido with a thin half inch layer black mulch to warm it up.
If you set your plants in cold ground, the growth will stall...I don't care where you live. This might be pointless if you live on the equator, otherwise, it would be wise to heed the advice of those who have learned the hard way or learn the hard way.
Soil temperature like water temperature is not taken on the surface. Don't hold me to it, but I believe soil temperature is taken 6" below the surface. Up here in Ohio, there can be a 50F surface temperature with frost 24" deep.
Two varieties of tobacco, Hicks, a flue-cured variety, and Resistant Havana 211, a cigar variety, were grown at soil temperatures of 46°, 59, 72° and 85°F. in a greenhouse. Three rates of each: N, P[SUB]2[/SUB]O[SUB]5[/SUB], and K2O were applied in a factorial combination. The best soil temperature for growth was around 72°F. as indicated by measurements of leaf weight, leaf area, number of leaves, stalk weight, and stalk length. The 46°F. soil temperature was too low for good growth. Resistant Havana 211 grew better generally at the low and high soil temperatures. Phosphorus appeared to be the most important and beneficial nutrient element for growth at the lower soil temperatures.
[h=2]Cited by[/h]View all 3 citing articles
Two varieties of tobacco, Hicks, a flue-cured variety, and Resistant Havana 211, a cigar variety, were grown at soil temperatures of 46°, 59, 72° and 85°F. in a greenhouse. Three rates of each: N, P[SUB]2[/SUB]O[SUB]5[/SUB], and K2O were applied in a factorial combination. The best soil temperature for growth was around 72°F. as indicated by measurements of leaf weight, leaf area, number of leaves, stalk weight, and stalk length. The 46°F. soil temperature was too low for good growth. Resistant Havana 211 grew better generally at the low and high soil temperatures. Phosphorus appeared to be the most important and beneficial nutrient element for growth at the lower soil temperatures.
[h=2]Cited by[/h]View all 3 citing articles
[h=3]How to Measure Your Soil Temperature
[/h]
The soil temperature for planting vegetables should be:
Tobacco and tomatoes are nearly synonymous.
[/h]
- Measure the Right Depth: If you are planting seeds or new plants, take your measurement at the recommended planting depth. If you’re measuring for a mixed garden, check at least 5-6 inches deep.
- Make a Pilot Hole: Use a screwdriver to make a pilot hole so that you don’t break your thermometer by pushing it into hard soil.
The soil temperature for planting vegetables should be:
- 40° F or warmer: Lettuce, kale, peas, spinach.
- 50° F or warmer: Onions, leeks, turnips, Swiss chard.
- 60° F or warmer: Broccoli, cabbage, cauliflower, carrots, beans, beets.
- 70° F or warmer: Tomatoes, squash, corn, cucumbers, melons, peppers.
Tobacco and tomatoes are nearly synonymous.
ChinaVoodoo
Moderator
That appears to be the study I provided a link to a few posts back.
Gavroche
Well-Known Member
[QUOTE = FmGrowit; 134518]
Le tabac et les tomates sont presque synonymes. [/ QUOTE]
Good...
21 C is 70 F
What is what there are examples of plantations of the tobacco on warm layer. Example on waste of litter of horse covered with earth(ground)?
est ce qu'il existe des exemples de plantations du tabac sur couche chaude . Exemple sur fumier de cheval recouvert de terre ?
Le tabac et les tomates sont presque synonymes. [/ QUOTE]
Good...
21 C is 70 F
What is what there are examples of plantations of the tobacco on warm layer. Example on waste of litter of horse covered with earth(ground)?
est ce qu'il existe des exemples de plantations du tabac sur couche chaude . Exemple sur fumier de cheval recouvert de terre ?
This is an interesting and in some instances a murky subject. Unless temps are extremely high, warmer is better (i.e. faster growth). I agree that traditional tobacco growing areas are easier, since growers were able to succeed at tobacco in those locations hundreds of years ago (prior to modern instrumentation and weather forecasting). Outside of those areas, as we know, growing tobacco can be wonderfully successful, though the technical requirements may be more stringent.
Prior to greenhouse (or indoor or closet) production of seedlings, seed beds were started outdoors, always a week or two after the known last frost date. This naturally postponed transplantation further into the summer, virtually eliminating the very question of the conditions required for transplant. Without "greenhouse" seedling production, tobacco growing in less favorable locations is often impossible, due to the shorter growing season. (60-90 days from transplant to harvest, plus 60 days from seed to ready transplant. That requires a 120 to 150 day growing season.)
Seed germination temps sometimes differ from suitable transplant temps.
A search for expert information on transplanting tobacco seedlings to the field pretty much leads to this FTT forum. That's us. Most extension service info is on how to raise transplants in a greenhouse, with little attention to planting them out.
Completely aside from air and soil temps that may be favorable (Mine were favorable back in early March!), we're still stuck with average date of last frost, and a check of the forecast for unexpectedly cold temps after that. If local temps have been persistently cold shortly before "last frost date," then checking soil temp will be important. If, on the other hand, local temps have been promising, I think you can just watch the calendar and the forecast.
http://www.gardeners.com/how-to/when-is-it-warm-enough-to-plant/9029.html
Germination rates of vegetable seed at various temps: http://extension.oregonstate.edu/deschutes/sites/default/files/Horticulture/documents/soiltemps.pdf [2 pages]
Bob
Prior to greenhouse (or indoor or closet) production of seedlings, seed beds were started outdoors, always a week or two after the known last frost date. This naturally postponed transplantation further into the summer, virtually eliminating the very question of the conditions required for transplant. Without "greenhouse" seedling production, tobacco growing in less favorable locations is often impossible, due to the shorter growing season. (60-90 days from transplant to harvest, plus 60 days from seed to ready transplant. That requires a 120 to 150 day growing season.)
Seed germination temps sometimes differ from suitable transplant temps.
A search for expert information on transplanting tobacco seedlings to the field pretty much leads to this FTT forum. That's us. Most extension service info is on how to raise transplants in a greenhouse, with little attention to planting them out.
Completely aside from air and soil temps that may be favorable (Mine were favorable back in early March!), we're still stuck with average date of last frost, and a check of the forecast for unexpectedly cold temps after that. If local temps have been persistently cold shortly before "last frost date," then checking soil temp will be important. If, on the other hand, local temps have been promising, I think you can just watch the calendar and the forecast.
http://www.gardeners.com/how-to/when-is-it-warm-enough-to-plant/9029.html
Germination rates of vegetable seed at various temps: http://extension.oregonstate.edu/deschutes/sites/default/files/Horticulture/documents/soiltemps.pdf [2 pages]
gardenersnet said:
extension.org said:
Bob
Brown Thumb
Well-Known Member
Well you just killed my experiment 
- Status
