will plants survive shipment without a heat pack?

no. bays and trucks are not heated. they will be smelly and cold by the time you open the bags

About a month ago I bought some plants from someone here, and most arrived dead. The smell in the bags, OMG, it was terrible. The plants were almost ice cold. The poor seller couldn't understand how the plants could have overheated, no, it was the opposite, the cold can kill, too. I don't know how long the plants had been exposed to the outdoor temps, which was no higher than the 40's, but it was enough to kill them. I learned my lesson, I am waiting for warmer temps before I start buying and selling plants again. Which is a pity, my tanks are becoming overrun by java moss and by spring there will be no room left for my fish.:headshake2:
 
not gonna fare too well at mid 30's for sure
 
I wouldn't trust it.
 
For that amount of plants a heat pack is cheap. 60 and 72 hour heat packs are available from most places that sell aquatic shipping materials, for about $3.00. Your plant seller will be able to sell through the Winter and make more money by pleasing customers. The package still needs to go overnight.
 
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