CRX EF 88

I went out to the garage to start my car today to let it run for a little bit to charge the battery up and it was completley dead. I have heard once the Odyssey dry cell batteries go all the way dead they are ruined. Any truth to this? I live in Ohio and my car is stored in the garage all winter so i need to figure out what to do to keep the battery maintained so that i dont have to buy a new one every year. I did a little research on some fourms and people said you have to get a special battery tender/charger for drycell batteries. I know alot of people run these batteries so i need your advice on what to do.