January 2023 - 14

TECHNICALLY SPEAKING
U.S. during different times of the year. For northern
locations and early spring production (flowering in March),
the heating cost per crop decreased for all species as
temperatures increased.
For more southern
locations and early spring
production, the heating
cost per crop decreased
as temperature increased,
but only for cold-sensitive
crops. For cold-sensitive
and cold-intermediate
crops, as well as for later
spring production, heating
costs per crop were less
sensitive to temperature
and crop time.
Higher humidity.
The amount of water that air can hold decreases with
temperature. Therefore, lowering the temperature usually
translates into an increase in humidity and decrease
in the vapor-pressure deficit (VPD). Except during
propagation, a recommended minimum VPD is 0.7 kPa,
To decrease energy
costs, it is tempting to
lower heating settings,
but this has several
consequences to the
crops growing inside.
which corresponds to a maximum relative humidity of
64% at 63° F, 70% at 68° F and 75% at 73° F. When the
VPD is lower (relatively humidity is higher), crop uptake
of water and nutrients
typically decrease and
some plant pathogens
spread more easily.
To conclude, lowering the
greenhouse temperature is
usually not recommended
when propagating plants,
or when finishing coldsensitive
crops, especially
for growers in cold
climates. A decrease in air
temperature usually leads
to higher humidity because
cooler air holds less water
vapor. Finally, a lower temperature usually translates into
less ventilation, which can lead to a deficiency in carbon
dioxide (CO2
) concentration. A CO2
deficiency greatly
decreases crop growth, leading to lower crop quality and
possibly a delay in flowering.
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4341 Round Lake Road Apopka, FL 32712
FERNS
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Bench tops attach
to any type of frame
LANDSCAPE
* A-V plastic Bench Tops are available in two sizes and may be
attached to any type frame.
* A-V plastic Bench Tops are strong enough to walk on when
properly supported and are UV protected for long life.
* A-V plastic Bench Tops provide a safe, smooth working
surface - no tipping or catching of trays and no sharp edges.
A-V International
P.O. Box 336, Broadway, VA 22815 USA
Phone: (540) 896-6378 * Toll-free: (800) 328-6378
FAX: (540) 896-7079 * Email: AgriAVINT@aol.com
www.a-vinternational.com
Circle 106
14
JANUARY 2023 GPNMAG.COM
CELL PACK LINERS
NEW VARIETIES
1 TRAY MINIMUM
PRODUCED IN THE USA
CONTACT US FOR MORE INFORMATION
AND REQUEST A CATALOG
(407) 889-8487 * Info@ag2tc.com
www.ag2tc.com
Circle 107
TROPICALS
SUCCULENTS

http://www.a-vinternational.com http://www.ag2tc.com http://www.GPNMAG.COM

January 2023

Table of Contents for the Digital Edition of January 2023

January 2023 - 1
January 2023 - 2
January 2023 - 3
January 2023 - 4
January 2023 - 5
January 2023 - 6
January 2023 - 7
January 2023 - 8
January 2023 - 9
January 2023 - 10
January 2023 - 11
January 2023 - 12
January 2023 - 13
January 2023 - 14
January 2023 - 15
January 2023 - 16
January 2023 - 17
January 2023 - 18
January 2023 - 19
January 2023 - 20
January 2023 - 21
January 2023 - 22
January 2023 - 23
January 2023 - 24
January 2023 - 25
January 2023 - 26
January 2023 - 27
January 2023 - 28
January 2023 - 29
January 2023 - 30
January 2023 - 31
January 2023 - 32
January 2023 - 33
January 2023 - 34
January 2023 - 35
January 2023 - 36
January 2023 - 37
January 2023 - 38
January 2023 - 39
January 2023 - 40
January 2023 - 41
January 2023 - 42
January 2023 - 43
January 2023 - 44
January 2023 - 45
January 2023 - 46
January 2023 - 47
January 2023 - 48
January 2023 - 49
January 2023 - 50
January 2023 - 51
January 2023 - 52
January 2023 - 53
January 2023 - 54
January 2023 - 55
January 2023 - 56
January 2023 - 57
January 2023 - 58
January 2023 - 59
January 2023 - 60
January 2023 - 61
January 2023 - 62
January 2023 - 63
January 2023 - 64
January 2023 - 65
January 2023 - 66
January 2023 - 67
January 2023 - 68
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-december-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/new-varieties-digital-guide-2025
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/2024-guide-to-cannabis-production
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-december-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/new-varieties-digital-guide-2024
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-july-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-april-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/2023-guide-to-hemp-production
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-january-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/2023-guide-to-cannabis-production
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-december-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-october-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/gpn-new-varieties-digital-guide-2023
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-july-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-april-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/cannabisguide-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/hempguide-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/newvarieties-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-january-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2022
https://www.nxtbook.com/greatamericanmediaservices/GPN/december-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-november-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-september-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-july-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-march-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/cannabisguide-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/hempguide-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/newvarieties-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-january-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2021
https://www.nxtbook.com/greatamericanmediaservices/GPN/december-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-november-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-september-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-july-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/californiaspringtrials-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-march-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/cannabisguide-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/hempguide-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-january-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2020
https://www.nxtbook.com/greatamericanmediaservices/GPN/december-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-november-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/november-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/october-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-september-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/september-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/august-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-july-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/july-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/june-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/may-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/april-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/californiaspringtrials-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-march-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/march-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/february-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/undercontrol-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/big-grower-january-2019
https://www.nxtbook.com/greatamericanmediaservices/GPN/january-2019
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