Seeding and Planting Charts - All of Them!

With the first month of the new year behind us, gardeners are focused on one thing ... the countdown to spring. We know in Colorado dates don't necessarily equate to the exact time or window to actually start planting outdoors. We often get snow in May. An excellent resource for climate summaries in Colorado that may also help you plan, click here.

When are all the best windows of indoor and outdoor seeding, planting and firing up the outdoor grill?  You've come to the right place, all my seeding and planting charts are here in one blog location. As for the grill, why even put it away for the season - we use ours all year.

For newbies or a review, here is a summary of the outdoor growing seasons along the Front Range. Add a couple of weeks or more for higher elevations. These windows and my charts below should help you plan when you'll start seeds indoors or direct seed outdoors or when the tomato plants purchased over Mother's Day weekend go in the ground.

There are three overlapping seasons to plant and direct seed outdoors. The cool-season planting period ranges anywhere from March to the first of May. These include cool-vegetables like spinach, peas and beets and cool-season annuals like pansy, calendula and sweet peas. Keep in mind that cool-season planting or direct seeding is all dependent on the weather - if snow is on the ground or it's raining or snowing from mid-March to mid-May, the cool-season planting window may either be delayed or skipped. Using tunnels, row covers and cloches are recommended if the weather isn't cooperating.

The warm-season window is anywhere from mid-May to the first of July and includes herbs like basil, vegetables - tomatoes, peppers, squash and corn, plus annuals - petunias, marigolds, sunflowers and cosmos. Hardy perennials, shrubs and trees can be planted during this time as well and all the way to early fall. The exception is to try to avoid planting when temperatures are extremely warm. It can be done, but pay close attention to watering and providing some shade.

Mid-summer is when the third season planting window begins - mostly cool-season vegetables that mature in sixty days or less and warm-season crops that also have a shorter maturity date like summer summer squash, okra and basil.

The timing, seeding and planting information on seed packets vary per company. Some mention soil temperatures or map zones as guides to direct seed outdoors, or a certain number of days from frost dates to start seeds indoors. Pay attention and familiarize yourself with the seed packet information. My charts try to accommodate most seed company packages. For tips on reading packets - Understanding the Seed Packet.
 

Vegetable seeds that you need to get started very soon indoors for early transplanting out in March to April include -  broccoli, Brussels sprouts, cabbage, parsnips, onions and celery. Tunnels or cold frames are recommended for early planting when freezes and frosts are the norm. Soil conditions need to be spot on too, not too wet, frozen or cold.

Keep in mind that if you miss the window to start your seeds indoors, you can always purchase cool-season transplants at garden centers starting in late winter into spring, and later in the spring for warm-season plants. Warm-season seeds are generally started indoors in late March to April for late May transplanting.