Batavia, Ohio (AP) -- Authorities in Southwest Ohio say warm but not too hot weather this summer has been good for growing the region's number 1 illegal cash crop, marijuana.

Clermont County Sheriff Tim Rodenberg says a roundup last week netted more than 1,500 plants, nearly five times the number seized last year.

Rodenberg says some of the plants were 8 feet tall, and the total seized in five townships east of Cincinnati would have been worth about $1.5 million.

The Sheriff says a helicopter and all-terrain vehicles were used in the sweep.

No charges have been filed. Rodenberg says it's sometimes hard to determine who is growing the pot because even the landowners don't know what is going in some remote areas.

(Copyright 2008 by The Associated Press. All rights reserved.)