Prep for a root knot nematode battle.......

[David from Dothan]

......as there appears to be no "quick fix" or even a "guaranteed" permanent "fix", at all. So......the plan is to follow the recommendations of fellow forum gardeners from the original thread.......(1) to take out all the dirt....(2) sterilize the dirt.....(3) put a bottom in the raised bed box....and it is at this point that I enter a brain-fart zone. The question being...."What kind of bottom can be put in a raised bed that will (1)...separate the sterilized raised bed soil from the bottom native soil....(2) allow proper drainage and, MOST IMPORTANTLY.....(3) at the same

time not allow the nematodes in the native bottom soil access to the sterilized bed soil." Even "creative" ideas will be appreciated.

 

[Chuck]

It looks like your raised bed is made of 4x4's. Why not get some corrugated tin and put a lot of holes in it. Then place the tin on top of the bottom 4x4? I don't know how wide your bed is but tin is 26 inches. You could nail a 2x4 to the centerline or from side to side as braces to keep the tin from bowing down. It will be 3 inches off of the ground and will drain. If you want your soil deeper just add another 4x4 on top.

How are you going to sterilize the soil?

 

[David from Dothan]

It looks like your raised bed is made of 4x4's. Why not get some corrugated tin and put a lot of holes in it. Then place the tin on top of the bottom 4x4? I don't know how wide your bed is but tin is 26 inches. You could nail a 2x4 to the centerline or from side to side as braces to keep the tin from bowing down. It will be 3 inches off of the ground and will drain. If you want your soil deeper just add another 4x4 on top.

How are you going to sterilize the soil?

Thanks for the suggestion, Chuck. One bed is 40 inches os/os and the other is 36 inches....which means I would have to add some 4X4 inside "framing" to accommodate the tin. I have intentions of sterilizing the box soil, as well as the native, bottom soil with boiling water (Don't get enough direct sun to utilize solarization techniques). How long do you suppose the corrugated tin would last before rusting out ?

 

[Chuck]

Thanks for the suggestion, Chuck. One bed is 40 inches os/os and the other is 36 inches....which means I would have to add some 4X4 inside "framing" to accommodate the tin. I have intentions of sterilizing the box soil, as well as the native, bottom soil with boiling water. How long do you suppose the corrugated tin would last before rusting out ?

You don't need 4x4 framing, 2x will work fine. IMO using boiling water is a waste of time. One has to maintain a temperature of at least 180F for at least 20 minutes. I'd guestimate the tin would last about 4 years. You could use plexiglass but it costs a lot more than tin but will be cheaper in the long term. And plexiglass is easier to work with than tin. It also comes in 4 ft widths but you will still need additional framing. Why even worry about the native soil. You can kill every last nematode there but they will just come back from the surrounding soil. The following picture shows how I sterilize my seed starting soil. It might give you an idea. It might be advantageous to just replace the soil in the beds. After you kill the nematodes every last bacteria and fungi will be dead too. This is OK for seed starting but is not really all that good when used as a garden soil. You can replenish the microbes but it takes time and is of some expense.

 

[David from Dothan]

You don't need 4x4 framing, 2x will work fine. IMO using boiling water is a waste of time. One has to maintain a temperature of at least 180F for at least 20 minutes. I'd guestimate the tin would last about 4 years. You could use plexiglass but it costs a lot more than tin but will be cheaper in the long term. And plexiglass is easier to work with than tin. It also comes in 4 ft widths but you will still need additional framing. Why even worry about the native soil. You can kill every last nematode there but they will just come back from the surrounding soil. The following picture shows how I sterilize my seed starting soil. It might give you an idea. It might be advantageous to just replace the soil in the beds. After you kill the nematodes every last bacteria and fungi will be dead too. This is OK for seed starting but is not really all that good when used as a garden soil. You can replenish the microbes but it takes time and is of some expense.

View attachment 56856

All GREAT points........Thinking Plexiglas is going to be the way to go. Rather spend the extra money now and not HAVE to be repeating in just a few short years.....Also, I did have concerns about destroying the GOOD micro-herds with the bad and the ugly dirt demons during sterilization, so leaning towards all new soil.....even though it's gonna take a butt-load.

 

[DirtMechanic]

Do not worry about the good microherd. You can add your own and fertilizer products like epsoma and jobes preblend it into their mix.

 

[David from Dothan]

Do not worry about the good microherd. You can add your own and fertilizer products like epsoma and jobes preblend it into their mix.

Yeah....but....but......I JUST got 'em trained not to go over the fence....they're a REALLY good microherd......

 

[Chuck]

Yeah....but....but......I JUST got 'em trained not to go over the fence....they're a REALLY good microherd......

In all reality, you will still have to replenish the microherd even with new soil. But that's why fertilizers and molasses was invented along with multitudes of other microbe growing soil additives. Probably the easiest way to round up the herd is with copiously applied aerated compost tea.

 

[DirtMechanic]

Yeah....but....but......I JUST got 'em trained not to go over the fence....they're a REALLY good microherd......

Open doors are allowing a two way flow!

 

[DirtMechanic]

IMO raised beds miss a design perfected by the potted plant crowd. Maybe its a scale thing, or a custom container build challenge. Seriously though, I would have a 1 inch or 2 inch at the most water pan under my raised beds. Epdm or water proof whatever but drainage rock or perlite under and prior and then whatever on top in the drier part of the bed. I have not done this, I have no experience with this save the various potted plants like our bromeliads that simply havea water pan. No nema could survive that barrier, and once the plants matured the roots would determine amongst themselves how many toes to dip into the water, all the while allowing a designed drainage.

Its not but a few steps to a controlled dutch bucket system, save where your water would spill out the dutch bucket would return to a tank for aeration and nutrient and pathogen control.

For a raised bed dutch bucket system, I could see a pan under the bed inside a spillover pan that is lower, and even might allow uv radiation sterilization. Pure fantasy on my part.

 

[David from Dothan]

A report from Texas A&M AgriLife Extension in "Aggie Horticulture"............"Organically, only the planting of cereal rye (Elbon) in the fall to grow during the winter will decrease nematode populations. Excessive drying of the soil during July will also help. Another possible solution may be the solid planting of French (small blooms) marigolds for 3 months in areas heavily contaminated with nematodes. The French marigold, when grown on soil infested with nematodes, suppresses the population of these nematodes and reduces the numbers found in the roots of susceptible host plants. Three compounds of an a-terthienyl type, toxic to nematodes, have been identified in root exudates from these plants. Terthienyls are released from growing roots, even without their decay, but benefits require three to four months to become clear. There is some evidence that a-terthienyl is inhibitory to some plant-pathogenic fungi too. Marigolds also function as a trap crop since larvae which penetrate the roots do not develop beyond the second larval stage and do not lay eggs."

Sooooo.........gonna fight 'em with the addition of heavy compost to the beds AND French marigolds starting NOW, cause........you just never know.......If that doesn't work, I'll back up 10 yards and punt.

 

[DirtMechanic]

I am sorry that my memory sucks, but I have heard a farmer volume member here swearing by the elbonian rye. I will look it up and report back.

I am seriously considering the rye in the pathways of my winter garden.

Something else to do..but maybe its easy at the farmers co-op

 

[Meadowlark]

I don't know what a "farmer volume" member is.....but I use Elbon rye every year and have done so over 30 years. Works perfectly especially when used in conjunction with legumes. I heartedly recommend the use of Elbon as a cover crop over soil sterilization. Especially so for someone who has never tried it....what have you got to loose? Soil sterilization is such a destructive measure....and it takes so long to build up perfect garden soils.

90% of my garden soil right now is in field peas getting replenished for fall garden. I'll come in with Elbon rye plus legumes and grains in September for what space I don't use for fall winter production.

Great stuff!

 

[DirtMechanic]

I don't know what a "farmer volume" member is.....but I use Elbon rye every year and have done so over 30 years. Works perfectly especially when used in conjunction with legumes. I heartedly recommend the use of Elbon as a cover crop over soil sterilization. Especially so for someone who has never tried it....what have you got to loose? Soil sterilization is such a destructive measure....and it takes so long to build up perfect garden soils.

90% of my garden soil right now is in field peas getting replenished for fall garden. I'll come in with Elbon rye plus legumes and grains in September for what space I don't use for fall winter production.

Great stuff!

It was you! Farmer volume means more than a 5 gallon bucket of produce!

 

[Meadowlark]

LOL, guilty as charged!

200 pounds of onions, 200 pounds of potatoes, 35 quarts of tomatoes, 20 quarts of pickled okra, 20 quarts of beets, 20 quarts of picked okra, 45 dozen ears of corn, tons of all kinds of beans, countless cucumbers, melons, carrots, broc, brussels, cabbage, etc. etc.

Yes, definitely more than 5 gallon bucket of produce.