By Jessica S Herwick
Re-using your
pots from last year can be a big money saver, and it reduces waste, which is
always a plus. Even so, thrifty gardeners should beware! You could be recycling all sorts of
problematic pathogens, damaging mineral/salt deposits or even last year’s weeds
in an effort to reduce your carbon footprint.
The difficult to
prevent white and gray rings that develop around your containers are mineral
and salt deposits that accumulate over time. These are unattractive to some
gardeners but can actually dehydrate a plant if the roots sit against areas
with extreme collections of these deposits. Spores and bacteria that cause mold, fungus and even root
rot can stick to your containers, but hide from the naked eye. This makes it impossible to detect
which pots are harboring trouble for your new plants. So, even if it looks
clean, it may not be. Many of
these pathogens will remain undetected until your seedlings are growing strong
and then - BAM! - Out of nowhere, problematic and often fatal plant illnesses
begin to crop up unexpectedly.
To diminish the
risk of transferring mold, viruses and harmful bacteria from one seedling to
the next, plan to sanitize your recycled pots, flats and gardening tools as you
plan for this year’s garden. Try
the following methods for easy, affordable sanitization of your pots, flats and
gardening equipment or see the links to read more about sanitization
methods. While you’re at it,
consider pasteurizing your old potting soil instead of purchasing new bags this
season.
EASY TO MIX BLEACH SOLUTION
You Will Need:
Chlorine Bleach
(Also known as household bleach. Use only unscented.)
Liquid Measurement Device
(You can use most anything: measuring cups to reused gallon milk jugs. It just depends on the amount of solution you need to mix.)
Rubber Gloves or Kitchen Gloves
STRENGTH OF SOLUTION: You want to mix a bleach and water solution that is strong enough to kill the harmful debris and break down remains from last year’s plants that might stick to the edges of the pots. At the same time, if the bleach solution is too strong, it will be difficult to rinse from the pots – especially clay, terra cotta or other containers made of similarly porous material. You do not want the bleach to come into direct contact with the new plants that you’ll eventually place into reused containers, so measure carefully, and the rest of the process will be a piece of cake.
SOLUTION RATIO: The rule of thumb ratio, and the recommendation from the Penn State Extension Office is a 1:9 solution, meaning 1/10 unscented, chlorine bleach to 9/10 water. The amount of solution you will need to mix will depend on the size and shape of the containers or equipment you are sanitizing. You need enough space to completely submerge your containers (or all pieces of metal for gardening tools) in a pool of the bleach solution. Test out a large sink, bucket or basin to ensure your materials will fit well; Base your ratio on the amount of liquid your basin will hold. Estimating is okay, but try to stay as close to the real math as possible.
CONVERTING: One gallon equals 16 cups; One tenth of that is 378.541178 milliliters, or 1.6 cups. For a gallon container you would mix 1½ cups bleach with 14½ cups water to total 16 cups of liquid solution – or one gallon. Simple math can help you determine the proper ratio, or you can try an online conversion site and let them do the math for you! The conversion sites I have found to be the easiest and most helpful are listed below.
http://www.onlineconversion.com/volume.htm
http://www.calcul.com/cooking-conversion
Hint #1: Mix the bleach solution in a standard five-gallon bucket, then transfer the solution into spray bottles, or back into empty bleach containers for later use. The fresher the solution, the stronger it will be. Solution will keep well over time, but looses its strength the longer it sits. If you cannot smell the bleach/chlorine in the water when you take a small sniff – if it doesn’t sting your nose at all - then the solution is no longer potent. Use this method to test old bottles of solution before using to ensure success.
Hint #2: Recycle your clear plastic, gallon milk jugs for easy measuring and storing! Set a few aside before you put your weekly recycling out on the curb. I mark off the line where 1½ cups of bleach sit on the outside of the milk jug with a sharpie. Then, when it’s time to mix, I fill the bleach to my pre-marked line (using a funnel) and fill the rest of the jug with lukewarm water. If I’m filling a five- gallon bucket, I do this 5 times, pouring the mixture in one gallon at a time. This also helps to mix everything up, eliminating the need to stir the solution.
ALTERNATIVE METHOD: If you are absolutely against using chlorine bleach, you might want to try using heat to sanitize in place of the bleach solution. After using dish soap and warm water solution to scrub debris from your pots or garden tools, submerge and soak in boiling water (180 degrees Fahrenheit at all times) for 30 to 60 minutes. The longer you maintain the temperature and continue the soak, the more pathogens you are killing off. Upon removing items from the hot water soak: Wash gently with mild soapy water (using dish soap again). Rinse until the water runs clear, and set in direct sun to dry for 12 hours.
May Not Be As Effective As Bleach Solution!!!
To Sanitize
Plastic and Terra Cotta Pots and Planting Containers
You Will Need:
Chlorine
Bleach (unscented)
Measuring Cup
or Gallon Milk Jug (See above Hint #2)
Warm
Water
Large
Bucket, Basin or Kitchen Sink (for soaking)
Unscented
Dish Soap
Scrub
Brush or Old Tooth Brush
Steel
Wool (for tough to remove mineral/salt
deposits)
Rubber Gloves
INSTRUCTIONS
·
Soak pots and planting containers in warm, soapy
water to loosen fragments of matter.
Use a scrub brush to scour the pots clean, scrubbing off any debris as
well as those nasty mineral/salt deposits.
·
Use Steel Wool for difficult to remove stains and rinse
with warm water until all the soap runs off.
·
Make a bleach solution: 1 part bleach to 9 parts
water (see above for more info.)
·
Completely submerge pots and planting containers in
solution and soak for 10 to 15 minutes.
·
Upon removing the containers, rinse with warm
water.
·
Scrub lightly with soapy water (using unscented
dish soap) and rinse well until soap runs off and water runs clear. Inspect for
remaining residue and repeat procedure if necessary.
·
Lay containers out to dry for 24 hours before
using. If possible, dry pots in
direct sunlight. Exposure to the
sun can also help to kill off certain bacteria.
NOTE: If stains or heavy residue still remain
after the sanitation process, it is not
recommended to re-use the pot. Discard any materials when sanitization is
unsuccessful. Some plastic pots can be recycled. If you’ve stored containers or flats from your local
nursery, you can often return them.
When I cannot sanitize a terra cotta pot, I break it into pieces and
bury them in the backyard, away from the garden and ornamental shrubs.
To Sanitize
Garden Tools
You Will Need:
Chlorine Bleach (unscented)
Measuring
Cup or Gallon Milk Jug (See Above
- Hint #2)
Warm
Water
Large
Bucket, Basin or Kitchen Sink (for soaking)
Unscented
Dish Soap
Steel
Wool or Wire Bristled Brush (for rust
build up)
Rubber
Gloves
·
Soak tools in warm, soapy water to loosen fragments
of matter. Use steel wool or a
wire bristled brush to scour the tool, scrubbing off any debris or rust spots.
·
Make a bleach solution: 1 part bleach to 9 parts
water (see above for more info.)
·
Completely submerge tools in solution and soak for
10 to 15 minutes.
Hint: If
the tool is cumbersome or oddly shaped, and you cannot soak it, try filling a
spray bottle with the fresh bleach solution. Spray the entire tool to the point of saturation (until
solution is dripping from the tool).
Allow to stand for 20 to 30 minutes before moving onto the next step.
·
Upon removing the tools, rinse with warm
water.
·
Scrub with soapy water (using unscented dish soap)
and rinse well until soap runs off and water runs clear. Inspect for remaining
residue and repeat procedure if necessary. Ensure all the bleach has been rinsed off (bleach is
corrosive and will cause rust if left on the metal of your tools).
·
Lay tools out to dry for 24 hours. If possible, dry
in direct sunlight. Exposure to the sun can also help to kill off certain
bacteria, and will help your tools dry completely – small areas around hinges
or other joints will collect water, and if not dried properly, or if bleach
remains, both conditions will cause rust to form on your tools.
NOTE: When you
are finished drying your tools, oil them before putting away. Use machine oil or penetrating
oil. Dip a dry cloth into the oil
and rub onto all metal areas of the tool.
Rub as if you are applying stain or oiling a pan for baking. Use a dry cloth or go over the oiled
areas to remove excess.
To Pasteurize
Potting Soil for Re-Use
You
Will Need:
An
Oven or An Outdoor Grill
High
Heat Thermometer
Old
cookie sheets
·
Preheat your oven to 180 degrees Fahrenheit.
·
Spread several inches of dry soil across the cookie
sheet. Do not overload the pan,
but utilize the space.
·
Place cookie sheet full of soil into oven.
Hint:
Heating soil inside an insulated oven can leave an odor for several days
after the process is complete. To
help prevent smell, heat oven to 200 degrees instead of 180 and leave the oven
door slightly ajar during the heating process then place a box of baking soda
into the oven once cooled, or try open broiling fresh lemons in a pan of water
to kill the stench.
·
Use your thermometer to take readings of the center
of the soil every few minutes.
When the soil temperature reaches to 212 degrees Fahrenheit or above,
most soil borne organisms cannot survive and the soil is considered sterile for
all standard potting purposes.
·
Remove soil from oven and place out to cool,
keeping soil on cookie sheet.
Hint:
Pasteurizing potting soil will kill all organisms – good and bad. Before re-using sterilized potting
soil, combine organic matter, compost, or slow release fertilizer according to
directions in order to rejuvenate you’re potting mix and replace necessary
minerals and helpful organisms.
Note that fertilizer can create higher amounts of salt deposits. Bone meal, blood meal and compost are
less likely to contain harmful salts.
.
ALTERNATIVE METHODS FOR PASTEURIZATION:
Outdoor Grilling Method: An outdoor grill works as well as an
oven, and will prevent the strange, earthy smell that cooking soil produces
from contaminating your house for 48 hours. Purchase or re-use large aluminum
roasting pans, fill with old soil, cover and place on the grill until
temperatures reach 212 degrees Fahrenheit. Stir once to encourage the soil to
heat evenly. Remove, cool, and mix in your organic matter to rejuvenate the
soil.
Boiling Water Method: Boiling
water can also kill off most of the harmful organisms lurking in your old
soil. Try poking holes in the
bottom of a large storage container, paint bucket, or other plastic
container. Fill 2/3rds of the way
with your old soil. Boil enough
water to pour continuously over the entire mass of soil. Pour the boiling water into the
container until the soil becomes muddy. Be sure to place your container in a
location where the boiling water can safely drain out through the holes at the
bottom of your container. A few
large stones along the bottom of your container will help with drainage if the
soil is very fine and clogs the holes.
Place in the sun, covered with black plastic (a cut up garbage bag will
do). When it is dry, mix in a
little organic matter and use.
To read more about sanitization and
pasteurization methods, check out the extension links and websites below:
The National
Garden Association has a website full of helpful hints and information
according to region. Check them
out at http://assoc.garden.org/about/
Timing is everything. To start your 
