Your new community garden project is off to a fantastic start! Depending on the time of year it is likely that you will start preparing your soil! How exciting! Most ground is going to require a good amount of compost. Order it by the truckload and you will save a lot of money. Most nurseries can deliver it with a dump truck or trailer and you can move it around with wheelbarrows. Plan on this for your first work day. You can dig it in lightly with pitch forks and use garden rakes to break up the soil. Trust me, take the time now to remove rocks and loosen the soil. The rewards will be in the plants, with the soil loosened they will have a much easier time putting out roots. More roots means bigger plants and more produce.
This is a picture of our new garden just after planting. Check with your local CSA's (community supported agriculture) if they have their own greenhouses they may be willing to sell you transplants at a much discounted rate. Explain what you are trying to do and how tight things are and you might just score your first donation.
Work days when everyone comes out at the same time to work in the garden are excellent for building community. Make sure to plan a couple of social gatherings throughout the year to help people get to know each other. A seed planting day early in the year can be followed by a transplant day. Make sure to bring along an ice chest packed with cold water. Its a great way to say thank you and show your club members you value their participation.
Later in the year plan harvest days together and perhaps organize a potluck using ingredients from the garden. You can take it a step farther by turning it into a fun completion Judge each others offerings and offer inexpensive prizes like gardening gloves to the winners. Remember to keep it fun and encourage everyone to participate. The more community you build the greater rate of success your garden will enjoy!