People have been trying to keep moles out of the garden since at least the 16th century when a garden writer of that time described a "sure fire" method of control. "Place a straight sided bucket in a hole in the ground to its rim and trap a female mole and put her into the bucket. Her cries for help will attract males that will also fall into the bucket in an attempt to rescue the female" Moles are after food when they make those tunnels you see in your yard and that food is earthworms, although they will eat grubs also (or about any other insect they find). Traps may kill a mole but another will move into that vacancy as soon as possible after you have eliminated that one, so trapping will be continuous. I know people that have trapped 100 moles every year for the last 40, or so, years and still do. The mole population has not diminished one bit. Poisons may help some, but they are poisons and could be eaten by other animals and since the dose of poison is aimed at moles could cause a larger animal excruciating distress over a period of time until it too died. Most places that have tried to replicate the studies done at Michigan State University have not. What Joe Vargas turf grass students learned is that to be effective you must apply 1 pint of Castor Oil over 5,000 square feet and then water it in thoroughly. None of the commercial products I have looked at have that much Castor Oil in the mix and all have on the label that this is meant to cover 10,000 square feet and as those turf grass students found too little will not be effective, and more is simply a waste of money. Every time Castor Oil has failed to control moles it is because it has not been applied properly. An unfortunate fact for every organic gardener is that because you will build up the amount of organic matter in your soil, and earthworms love organic matter, you will have a mole, most often only one simply because of the amount of territory each mole needs to supply its needs, anbout 1/4 acre.

Hi guys, I just saw this thread. This isn't my repellent though, credit is due to the Hosta forum (can't remember exactly where I read it). Also learned about the 12.5% ammonia or vinegar solution for slugs on the Hosta forum (I can vouch that the ammonia works great). Apparently there are many critters and pests that love Hostas! I just love the fact that these solutions are 100% organic and cause no harm to the plants (and hopefully to beneficial critters). The castor oil repellent saved many perennials and whatever few remaining bulbs in my front garden from certain demise. Saved the last 2 native Wild Hyacinth I started from seed, which take several years to bloom, from becoming vole food!! I like to make it a little strong, maybe 1-2 TBS castor oil and 2 cups of urine in per gallon. I think the castor oil makes the roots and soil around the roots distasteful to the voles, it is very sticky and lasts for 2-3 months. Not sure what the urine does, perhaps the smell repels them also, if so male urine is likely stronger. Also it's a great nitrogen-rich fertilizer. This post was edited by terrene on Fri, Sep 6, 13 at 5:52

the concern.. is a non sequitur ... just plant the darn tree ... and deal with the mole separately ... there ought to be a couple thousand mole topics if you use the GW search ... i am not of the camp.. that they are touchy feely creatures that benefit my life.. and my twisted ankle proves such ... they can all rot in mole hell ... lol ... but i digress ... lol ... ken ps: i would NEVER plant a tree in late july/august.. in my MI z5 ... just because you buy it.. or obtain it.. does not mean that is the best planting time.. it depends where you are.. and the ambient weather.. or whether you are gal .. lol ... its not that it cant be done.. i am talking about your experience level.. and making it easy ... you could discuss that in the tree forum if you wish ... Here is a link that might be useful: link

Technically, no oil wants to mix with water. :-) But castor (mostly ricinoleic acid) really doesn't make friends with much of anything easily and is extremely thick. Fun fact: In addition to being a gentle laxative, the stuff's great in soap...in very small amounts. It adds body to the lather like you wouldn't believe. In larger amounts, it just makes soft, sticky soap that's terrible and tends to develop DOS (Dreaded Orange Spot) very quickly. Really, in terms of annoyance, any good oil should do, with the thicker ones being preferable. But if you want a scent repellent, I wouldn't choose castor. It simply doesn't have much in terms of scent and costs a fortune. The dogs are neither repelled nor attracted to it (seriously, I keep seven pounds of the stuff on-hand...), so I don't think it would have too much impact on rodents. Going with 1 oz neem in a cheap carrier. Citronella, dragon's blood, or any other long-lasting, potent base note would be far more effective.