It’s the busiest time of year in vegetable gardens, as green thumbs plant the last rounds of seeds and seedlings for a fruitful summer crop.

Of course, there’s an art to when and how to plant to improve the chances of a happy harvest.

It mostly comes down to two age-old farming practices: watching the skies and cultivating the soil. That’s the word from Courtney Delello, the manager of Rutherford Gardens, a three-acre fruit and vegetable oasis along Highway 29.

When planting seeds the key, according to Delello, is to make sure you keep things damp.

“You have to keep them moist. If they dry out its over,” Delello said while wheeling a seeder, a contraption resembling a tiny wheelbarrow, down freshly tilled rows to evenly scatter carrot seeds.

Planting seedlings or greenhouse starts calls for a bit more technique. It’s important to acclimate the young plants to life outside the greenhouse by placing them outside for two to three hour spells everyday for one to three weeks — a process called “hardening off”— before planting the seedlings in the ground, Delello said.

Overcast skies on a cool afternoon are what every farmer hopes for when planting. But if ideal conditions don’t occur, Delello said, it’s best to plant starts late in the afternoon so they don’t have to endure hours upon hours of sunlight on top of the already intense shock of being transplanted into the ground.

“It’d be great if there’s a nice steady rainfall after you plant. That way the soil is soaked and they’re off to a good start,” Delello said. “We can do that with irrigation, but its always nice if the weather cooperates.”

She said summer crops including tomatoes, melons and squash can’t be put in the ground until the weather has warmed to where the lows at night are reliably well above freezing.

For long-term success of gardens, crop rotation within any patch of soil is important.

“Fungal diseases tend to attack the same family of plants,” she said. “And different crops have different nutrient requirements,” which means planting the same crop in the same spot year after year could deplete certain nutrients from that soil.

“A lot of what you end up doing is figuring out how to best use your space, what crops go where, and moving stuff around is an important part of sustainable agriculture,” she said.

Soil improvement is also a must to encourage any garden’s prosperity year in and year out.

“We’re always adding in organic matter and doing soil tests to make sure we have healthy levels of phosphorous, potassium and calcium, all the stuff the plants need,” Delello said.

Laddie Hall, who co-owns and runs the Rutherford Gardens as well as Long Meadow Ranch winery, sees soil improvement as an integral part of her commitment to farming organically — that means no synthetic pesticides, no fertilizers.

“A huge part of what we do is building our soil. We have less problems with pests and it’s actually a lot easier to add in compost,” Hall said — gesturing to a tractor-sized mound of compost at the garden’s eastern edge — “than have to worry about synthetic fertilizer.”