This is a public-interest archive. Personal data is pseudonymized and retained under GDPR Article 89.

Re: Cold Frame and Hardening Off

Hmmm....first, what kind of seedlings are they?

----------
> From: AG <agal@emory.edu>
> Date: Friday, February 13, 1998 7:36 AM
> 
> My seedlings are happilly growing under fluorescent
> lights.  At some future point I will need to begin
> hardening them off.  
> 
> My basic questions are:
> 
> 1.  When do I begin this process?  Our days are approching
>     highs of in the upper 50's and nights in the mid 30's.

Sort of depends on what they are IMO.  Tender annuals need to wait until
temps are warmer; plants that like cool weather can be started sooner, but
I'd tend to wait until your days were in the 60's and nights in the mid to
upper 40's...without any additional protection.  If you put them in a frame
and close it at night, you can start earlier.
 
> 2.  Is a cold frame necessary?  
>     Where do I find a link on construction of one?

No, but can save a lot of trucking pots in and out.  It has the drawback of
needing careful monitoring as heat can build up quickly and cook tender
seedlings.    Sorry, don't know of a link right off.  You can, if you want
something temporary, get some bales of hay or straw, form them into a
hollow square and drape clear plastic over the lot.   Or use railroad ties
or concrete blocks...anything that puts the plastic above the foliage. 
I've even done jerry-rigged constructions out of bent and tied bamboo and
plastic or you can fashion an 'A' frame from wood and drape it in plastic. 
All of the above need to be watched since there is no way to automatically
open the plastic when the sun starts to heat up the inside.  
 
> 3.  Can I just place the younng  plants in a warm partly
>     sunny place and bring them indoors at night?

Yes, you can do this.  You would want to start out with them outside for
only an hour or so and then increase the time.  It's not only sun, but wind
that can damage tender leaves.  The whole process takes a couple of
weeks...building up time gradually  until they are used to the real world.

If you wait until temps are nice and warmed up, you can bring seedlings out
into the shade and just protect them from wind for a few days without
having to worry about covering them against cold..then you can shift them
into the sun gradually over a week or so.  This would mean nights in the
50's consistently....again, depending on just *what* plants your seedlings
are.
 
Marge Talt, zone 7 Maryland
mtalt@clark.net
Editor:  Gardening in Shade
http://www.suite101.com/frontpage/frontpage.cfm?topicID=222
Gardening Topic Index for Suite101:
http://www.suite101.com/userfiles/79/gardening.html

Don't miss the Spring Rose Workshop, 2/1 - 2/14:  Details at:
http://www.suite101.com/userfiles/79/roseshop.html.
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index