So we forgot one small PI plant in the backyard and it got mown over. I see plenty of info on washing equipment with dawn soap and water, but what can I do about the contaminated yard?? I ask because we have a toddler who plays back there, so this is pretty important to me. If I sprayed water/soap mix on the grass to get the oils to wash down into the dirt, would that work? Would it kill the grass?
First, what kind of a mower? Push or gas or electric. Were you bagging the clippings? Any tiny piece of poison ivy will have Urushiol which causes the allergic reactions. I'd take a good blower and blow that lawn well, pushing the tidbits into your plant beds. Sounds as if you will have to always be alert for poison ivy anyway. Little rubber boots, long sleeves...heck a hazmat suit! I am being silly now. There is a product called bentoquatam one can apply to skin to make a protective barrier. I would most certainly ask the pharmacist even though this is over the counter, for use on toddlers! I am wondering if there aren't other protective barriers such as calamine...something that won't cause the piece of plant to stick and 'melt' so to speak. Something dry. You will always have to worry about this. What is your or your wife's reaction to poison ivy? Your baby will inherit the propensity of course. If it is severe verging on anaphylaxic shock or tightening of the throat to inhibit breathing, I would always throw a huge sheet, blankets out on the lawn to play upon.
I would try spraying the area with soapy water, preferably a biodegradable type. I would use doctor bronners sal suds soap. Spray it, scrub it with a brush or something and then wash the grass off with plain water so it goes into the soil. This probably won't be 100% effective, but good news! Grass grows and within a few weeks and a few mows, the area will be fresh grass that wasn't exposed to the oil. For the meantime, use a blanket over the grass, keep your kid off it, or just wash your kid with dish soap, doc bronners sal suds or any grease and oil removing soap. I use a soap bar for my body after I've been exposed (which is very often) that is specifically formulated for removing poison ivy. You can buy them in health food stores.
Also, something to think about....It might not be such a terrible thing to be exposed to poison ivy every now and then. Especially as a young human, being exposed to allergens can help their body build immunities and become stronger. A lot of hill folk around here (not saying this is science) eat a baby poison ivy leaf in the spring for this reason. Seems to work out alright for them, buy yeah, just something to think about!