Temperatures?

[jpiper82]

Charlie,  It is getting later in the year, and for those of us who are growing 4" and 6" pots that have been recently acquired from HVH, what would your recommendation be as to when we need to bring them into a more stable environment.  We don't want to hurt the CV's but there is probably a optimal temp. to get them out of the cold for their own health. What say you?

John

[Charlie]

Hi John,

Good question. I would bring them inside when the nights drop below 45F (7C). If the days are warm and sunny it is less important but if the days are below 70F (21C) and the nights below 45F (7C) then for sure bring them in. I've seen a lot of cases where the hibiscus were left out until the first frost and then brought in and that is an invitation to fungus disease to attack stem tips or even systemically. Also as night temperatures drop some areas will get a lot of dew on the plants and that is not good for them either. It's always a combination of factors such as temperature, sunlight, and moisture that affect the health of hibiscus but if you are not sure then use 70F days and 45F nights as the minimums that the hibiscus are allowed to stay out.

Charlie

[blupit007]

I searched for this forum just now because I don't know what I should do.  It is dropping to the 50's at night now, but is still in the 80-90's during the day.  I am really cold right now, it is midnight, and I am considering going outside and bringing them ALL in!!  It is 59º and only supposed to get to 55º tonight, but be back in the 80's tomorrow.  By what you said above, I am planning on leaving them out.  I already figured out that the 4" plants that I bought from you last month do not like the 50º's at night, so they have been coming in each night, then back out in the sunshine in the morning.  But I have not made the move for the older 4" I have.

My question is, I am leaving this Friday for a one week vacation.  My mother is going to feed the cat and water my hibiscus while we are gone.  Supposedly the cut off date for risk of frost for our area is September 15.  Should I bring them all in the house, where they will not get a ton of direct sun light before I leave, or should I leave them outside, but put them under the eve of the roof so they still get the intense daytime sunshine?

[Charlie]

Hi Kristen,

It is pretty early still, but I wouldn't take any chances and would bring them indoors for the time you are gone. Hibiscus can get a pretty strong shock from cold but the lower indoor light will not be a shock. They might slow down their growth if the light is too low but they will remain healthy. You could check out the long term forecast the day before you leave and if the weather is forecast to stay above 50 then they would be fine outside but, if you have any doubts, bringing them inside is the safest way to go.

Charlie

[blupit007]

Thanks Charlie,  I think I would be so devastated if I were to loose any.  I am taking no chances, New England if famous for its temperamental weather changes...  I have some south facing windows that I will smush them all into, they should be happy there, then that way if it is a rainy week, they don't drown.  Also, my mother wouldn't have to water them as much, right?  Or will she because it will be pretty warm inside with the air off and windows closed.