Humanity has always had a connection with the earth, said John Stolzle, a Colorado State University Extension agent in Jefferson County who specializes in horticulture, plant pathology and food systems.

“Gardening is a direct way for people to interact with nature’s processes,” Stolzle said.

However, with the state’s diverse — and often unpredictable — weather, Colorado can present greater challenges to gardeners than many other U.S. states.

Luckily, Stolzle said, “there are a few tips and tricks that can help when starting up spring and summer gardens.”

It all depends on the last frost

Planting in Colorado is highly weather dependent and each year is different, Stolzle said.

But one tip to remember is not to start too early, Stolzle said.

“The key, in my opinion, is to be patient,” he said. “And to plant according to the last predicted frost date.”

Because the latter varies regionally, paying close attention to local weather forecasts may be the best bet. In general, gardeners can best-guess that the last frost date will likely be sometime late April or early May, Stolzle said.

PlantTalk Colorado, a resource for Coloradans to find research-based gardening information specific to Colorado’s diverse climate, suggests that “people in the Denver metropolitan area normally use Mother’s Day as a guide for when to plant.”

This year, Mother’s Day falls on May 12.

For those who want to get an early start on their gardens, Coloradans can plant seedlings indoors, then transplant them outdoors when the weather is appropriate.

General recommendations on when to start plants indoors range from two to eight weeks before transplantation, Stolzle said. But to get a more exact time frame for each plant, he said, seed packets will usually include the specific recommendations for that plant.

Acclimating plants to the outdoors before planting them outside can also help, Stolzle said.

But, to “avoid shocking their systems, plants should be introduced to the outdoors slowly, over time,” Stolzle said.

Grandma’s tip to avoid a freeze

The location of a plant, the duration of a cold spell and temperature can all play a part in a plant freezing, Stolzle said.

For example, “plants on the southern side of buildings and south-facing slopes will emerge from the soil relatively sooner, because the location is warmer,” Stolzle said, but “can then be at a greater risk when it comes to frosts.”

A Colorado Master Gardener reference sheet published by Colorado State University Extension notes that “grandma’s old method of covering the garden with blankets and sheets works well as long as the fabric remains dry.” The cover should be placed in the evening before a frost is suspected, but it must be removed the next day so the sunlight can recharge the soil with heat.

Cool versus warm season veggies

“Knowing the difference between cool and warm season vegetables can save a lot of headache,” Stolzle said. “But, in all of these cases, a cold, hard freeze will likely kill any plants left out or left unprotected.”

Hardy, cool season vegetables: Hardy, cool season vegetables prefer cooler temperatures and can likely survive a “frosty nip,” Stolzle said. They can be planted outside about two to four weeks before the anticipated last frost date of the season. Examples include onions, some spinach, lettuce, radish and broccoli.

Tender, warm season vegetables: Tender, warm season vegetables do not tolerate frost and need higher temperatures to grow well, Stolzle said. They should be planted when daytime temperatures are above at least 55 degrees Fahrenheit. Examples include cucumbers, New Zealand spinach and summer squash.

Sensitive vegetables: Some vegetables are even more sensitive than the tender, warm season vegetables, Stolzle said. These can only tolerate a low temperature of about 60 degrees Fahrenheit and prefer temperatures between about 70 to 95 degrees Fahrenheit. Examples include tomatoes, peppers, pumpkins, watermelon and eggplant.

The GrowHaus’ annual Seed Swap

“The weather is warming up and spring is almost here,” said Nathan Mackenzie, the director of development for The GrowHaus, a nonprofit indoor farm in Denver that has a mission to ensure everyone has access to healthy food.

Approaching the cusp of the growing season, The GrowHaus’ annual Seed Swap is a way for all gardeners and veggie lovers to get access “to as many seeds as you want to take home,” Mackenzie said.

“But it’s much more than just getting seeds,” Mackenzie said. “It’s all about bringing people together from all across Denver to celebrate the start of the growing season and the community we build through food.”