In the weeks before the popular Mother’s Day weekend plant sale, the dozen greenhouses at the 78th Street Heritage Farm start to swell with growing plants.There’s something different in each greenhouse. Fifty-two tomato varieties in one, herbs and veggies in another, hardy fuchsias, hanging baskets, shade plants, house plants. Flowers for the Welcome to Washington sign are housed here, too.Behind the scenes, volunteers tend to thousands of plants, ensuring they’re ready to be sold at the annual Master Gardener Foundation of Clark County’s sale. The sale supports the Washington State University Clark County Master Gardener program and the foundation’s grant program. It’s one of several springtime plant sales happening around Clark County to benefit nonprofits and schools.The Master Gardener Foundation supports some of the smaller garden programs around town, giving out $35,000 in horticulture grants each year.“That’s what all this is for — to give back to the community,” said Nancy Funk, a Master Gardener Foundation board member.Funk said the Master Gardener Foundation distributes grants in January and then visits sites in the summer to see how their projects are coming along.“And how we can help them, too,” she said.Cultivating history at fortOne such site that reapplies for a grant each year is the interpretive garden in front of Fort Vancouver. Funk said the grant is used to purchase seeds, starts, organic compost and fertilizer.