I forgot that I need to automatically subtract 2~3º from the official forecast for cooler temps to ajust for my garden's microclimate (unfortunately this rule doesn't apply when it's hot )
I'm a bit worried about some of my plants outside, but it's really WAY too early to think about covering them or bringing the container plants in.
These are what I have in my notes for Minimum Nighttime Temperatures. I posted the first set, maybe 2nd set too, before in response to someone's thread, but I wanted to start a new thread and ask you all for opinions and contributions. The first set is temperatures at which the plants will stay healthy. The 2nd set is temperatures that the plants can "survive" and "recover".
The USDA zone hardiness implies that the plants will lose foliage and go dormant before temps drop to those minimum temps, so to avoid dormancy, they need to be brought inside earlier -- at least 5°F higher than the minimum, I think. I've left them out to near minimum and they drop leaves/die down and sulk for a while, which can lead to panic -- "Oh no! I killed it!"
So let me know what you think. Post corrections and additions and let's see if we can turn this into a handy reference guide.
MINIMUM NIGHT TEMP:
Peppers
- ideal daytime temp of 75°~85°F and night temp of 55°~65° F Max 100ºF
- After transplanting, the optimum temperature is approximately 23ºC (73ºF) by day and 18-21ºC (64~70ºF) at night. Minimum soil temperature 20ºC. Max day temp 35ºC (95ºF) - dormant until lower Fall temp.
Eggplant
- ideal daytime temp should be in the range 80°~90°F and night temp should not go below 60°~65°F. Growth retarded at 60ºF
Peter1142 wrote:I really don't think it is so simple. For instance, my Hansel and Galine eggplant and Ace and Biscayne peppers have no issues with nighttime temps down into the 40s. Also if the soil is warm it keeps the plants warm, and the duration of the low temp matters also, all night or several minutes is a huge difference. If I did not plant until nighttime temps were always above 60F it would not be possible to grow these things here. Minimum soil temps are far more important IMHO but that still varies based on variety and plant size etc.
GROWTH STOP/Enter Dormancy Threshold TEMP
------------------------------------------------------
Basil - 60ºF
Eggplant - 60ºF
Pineapple - 60°F
Stevia - 60°F
Banana, Super
dwf. cavendish - 55°F
... BANANA minimum ...
https://www.sherrysgreenhouse.com/oldsite/banana.htmlWarmth, but not too much or too little! Specifically, growth stops and heat stress will occur at 100 degrees Fahrenheit (38 C). On the other end of the scale, a temperature below 42 degrees Fahrenheit (6 C) will cause leaf chlorophyll destruction. Freezing is obviously not a good thing for a banana plant, but the underground rhizome may survive if the cold temperature period if brief. Kiss the leaves goodbye, though.
...
Coffea arabica - 55°F
Peppers - 55ºF
Zinzibar officinale
(edible ginger) - 55°F
Tomato - 50ºF
Nasturtiums - 48ºF
--
I also have the following in my notes:
**Bring inside at least 5°F above highest zone temp to AVOID dormancy**
Based on USDA Hardiness Zone Map at https://www.usna.usda.gov/Hardzone/hzm-nw1.html
BRING IN ABOVE 60°F
-------------------------
Orchid 55 ~ 60
Chenille plant 55 ~ 60
Coffea arabica 55 ~ 60
Jasmine, Maid of
Orleans 9 (20) ~ 11 (40)
Pineapple 10b (35) ~ 11 (40)
BRING IN ABOVE 55°F
-------------------------
Basil 50
Banana, Super
Dwarf Cavendish 40
BRING IN ABOVE 50°F
-------------------------
Lemon, Meyerii 10a (30) ~ 11 (40)
Norfolk Island Pine 10a (30) ~ 11 (40)
BRING IN ABOVE 45°F
--------------------------
Aloe vera 10b (35) ~ 11 (40)
Grapefruit 10b (35) ~ 11 (40)
Lime 10b (35) ~ 11 (40)
Lemon Grass 10b (35) ~ 11 (40)
Night Blooming
Cereus 10b (35) ~ 11 (40)
Lemon 10a (30) ~ 11 (40)
Mango 10a (30) ~ 11 (40)
Rubber Plant 10a (30) ~ 11 (40)
Jalapeño 9 (20) ~ 11 (40)
Stevia 9 (20) ~ 11 (40)
Geranium 9 (20) ~ 11 (40)
BRING IN ABOVE 40°F
--------------------------
Amaryllis 8, 9 (20) ~ 11 (40)
Avocado 10a (30) ~ 10b (35)
Lemon Verbena 9 (20) ~ 10b(35)
Fuchsia 9 (20) ~ 10a (30)
Pineapple Sage 8 (10) ~ 11 (40)
Fig "Petite Negra" 8
BRING IN ABOVE 35°F (frost warning)
------------------------------------------
Rosemary 7a (0 °F) ~ 7b (5 °F)
Parsley 7a (0 °F) ~ 7b (5 °F)
Thyme, VarLemon 7a (0 °F) ~ 7b (5 °F)
(DORMANT STORAGE IN GARAGE ABOVE 28°F and foliage drops)
Pomegranate 10b (35) ~ 11 (40) <-- allow to go dormant
Overwintering
Hot peppers <-- allow to go dormant
Pineapple Sage
Venus Fly Trap (store dormant in cooler for insurance)