How Do I Sterilize Last Seasons Potting Mix To Help Prevent Whitefly Infestation?

Quickstrike · March 31, 2011

It seems like every season my mothers tomatoes are absolutely infested with whiteflies. She has been using several of the same half whiskey barrels for many years now - rarely changing/amending the soil between seasons.

It is my understanding that whiteflies lay eggs in the soil and emerge when it is warm again outside?

I plan on emptying the old mix into her flower garden bed.. scrubbing the whiskey barrels with a bleach solution and using all new homemade 'Als 5-1-1 Mix'.
Are there any other chemicals I should be using, or will bleach work?

Now.. here is my main concern. My Earthtainers were placed several feet away from her barrels. Although my plants were never decimated by the whiteflies, I did see a few on some of the leaves - by the end of the growing season.
Since my Earthtainers were brand-new last year.. with fresh bales of Pro-Mix BX, I would like to use it again for this season (with some additional perlite + bark fines ammended into the mix - as recommended by rnewste.)
What should I do to 'treat' this mix so that the [possible] whitefly eggs are destroyed?

Thanks for your help.

BlackestKrim · March 31, 2011

If you are concerned the whiteflies will start trying to colonize the tomatoes on your earthtainers, perhaps introducing some parasitic wasps would help.

That site also recommends silver/aluminum mulch to deter whiteflies. I thought they laid their eggs on the leaves rather than the soil? You might want to see if there are weeds or other plants that could be hosting whiteflies when the tomatoes are gone- they can affect a large variety of plants.

platys · March 31, 2011

Darn, I had a nasty white fly problem last year, and was hoping to reuse the potting soil (My husband will have a heart attack if I don't.

If I get the wasps right away, will they stick around until white flies show up?

Tom C zone 4/5 · March 31, 2011

Hows about not reusing old medium?

My end of the wager is fresh is cheeper, than fixing the old.

Heritage · March 31, 2011

Whiteflies lay their eggs on the underside of leaves and spend their life-cycle on the plant. Also, I don't think they can overwinter in Calgary freezing winters. (assuming the pots are outside) Here, they live year around and rotate between host plants.

Instead of sterilizing the soil I would look for the source of the whiteflies. Does your Mom buy any of her plants from a greenhouse? If you start seeds indoors do you have any houseplants infected with whiteflies that could infect your seedlings?

I would also use yellow sticky traps to monitor the whitefly population outside and begin spraying with an organic oil (like Neem oil, etc,) if the yellow traps are trapping whiteflies.

Steve

rnewste · April 1, 2011

Last Season, I was hit with Aphids, Psyllids, and Whiteflies. As part of my countermeasures this Season, I am trialing silverized mulch to reflect sunlight on the undersides of the leaves.

We'll see if it is an effective deterrent.

Raybo

Heritage · April 1, 2011

Raybo,

Interesting... I'm interested in seeing the results, keep us posted. I've heard good things about reflective mulch but haven't decided to make the investment just yet.

Steve

David Marek · April 1, 2011

Quote:

Originally Posted by platys

Darn, I...was hoping to reuse the potting soil

Sometimes I dump used potting soil in a pile and give it a "year off". Seems to help.

Quote:

Originally Posted by BlackestKrim

You might want to see if there are weeds or other plants that could be hosting whiteflies when the tomatoes are gone- they can affect a large variety of plants.

In addition to that perennials can carry viruses through the winter. I will be pulling some chlorotic milkweed I suspect is harboring cucumber mosaic virus. (sorry monarchs)

rnewste · April 1, 2011

Quote:

Originally Posted by Heritage

Raybo,

Interesting... I'm interested in seeing the results, keep us posted. I've heard good things about reflective mulch but haven't decided to make the investment just yet.

Steve

Steve,

It is not really that expensive. I bought mine from a fellow TV member who sells it on eBay:

http://cgi.ebay.com/Silver-reflectiv...item4158136086

Raybo

March 31, 2011	#1
Quickstrike Tomatovillian™ Join Date: Apr 2010 Location: Calgary, Alberta, Canada! Posts: 37	How Do I Sterilize Last Seasons Potting Mix To Help Prevent Whitefly Infestation? It seems like every season my mothers tomatoes are absolutely infested with whiteflies. She has been using several of the same half whiskey barrels for many years now - rarely changing/amending the soil between seasons. It is my understanding that whiteflies lay eggs in the soil and emerge when it is warm again outside? I plan on emptying the old mix into her flower garden bed.. scrubbing the whiskey barrels with a bleach solution and using all new homemade 'Als 5-1-1 Mix'. Are there any other chemicals I should be using, or will bleach work? Now.. here is my main concern. My Earthtainers were placed several feet away from her barrels. Although my plants were never decimated by the whiteflies, I did see a few on some of the leaves - by the end of the growing season. Since my Earthtainers were brand-new last year.. with fresh bales of Pro-Mix BX, I would like to use it again for this season (with some additional perlite + bark fines ammended into the mix - as recommended by rnewste.) What should I do to 'treat' this mix so that the [possible] whitefly eggs are destroyed? Thanks for your help.

March 31, 2011	#4
Tom C zone 4/5 Tomatovillian™ Join Date: Jan 2007 Location: SE Ohio Posts: 253	Hows about not reusing old medium? My end of the wager is fresh is cheeper, than fixing the old. __________________ Beyond the mountains, there are more mountains.

March 31, 2011	#2
BlackestKrim Tomatovillian™ Join Date: May 2009 Location: Austin, Texas Posts: 147	If you are concerned the whiteflies will start trying to colonize the tomatoes on your earthtainers, perhaps introducing some parasitic wasps would help. That site also recommends silver/aluminum mulch to deter whiteflies. I thought they laid their eggs on the leaves rather than the soil? You might want to see if there are weeds or other plants that could be hosting whiteflies when the tomatoes are gone- they can affect a large variety of plants.

March 31, 2011	#3
platys Tomatovillian™ Join Date: May 2010 Location: Naperville, IL Posts: 176	Darn, I had a nasty white fly problem last year, and was hoping to reuse the potting soil (My husband will have a heart attack if I don't. If I get the wasps right away, will they stick around until white flies show up?

March 31, 2011	#5
Heritage Tomatovillian™ Join Date: Nov 2010 Location: San Diego Posts: 1,255	Whiteflies lay their eggs on the underside of leaves and spend their life-cycle on the plant. Also, I don't think they can overwinter in Calgary freezing winters. (assuming the pots are outside) Here, they live year around and rotate between host plants. Instead of sterilizing the soil I would look for the source of the whiteflies. Does your Mom buy any of her plants from a greenhouse? If you start seeds indoors do you have any houseplants infected with whiteflies that could infect your seedlings? I would also use yellow sticky traps to monitor the whitefly population outside and begin spraying with an organic oil (like Neem oil, etc,) if the yellow traps are trapping whiteflies. Steve

April 1, 2011	#6
rnewste Tomatovillian™ Join Date: Apr 2007 Location: Campbell, CA Posts: 4,064	Last Season, I was hit with Aphids, Psyllids, and Whiteflies. As part of my countermeasures this Season, I am trialing silverized mulch to reflect sunlight on the undersides of the leaves. We'll see if it is an effective deterrent. Raybo