Botany and Seed Starting

The previous two weeks of the Master Gardener program have been focused on botany.  Botany!!  Oh my!  Do I really have to know this?  Well, when it comes to seed starting it really helps to understand the basic anatomy of a seed.

Did you know that you should only plant a seed at a depth that is one and a half times the width of the seed?!?  Many of us have a tendency to just poke our finger into the dirt to make a hole, drop the seed in and cover it up.  Well that might work okay for a sunflower seed or a lima bean but think about a little tiny lettuce seed.  So why is that?


A seed is basically made of three main parts - the embryo, the food source, and the seed coat.  A  tiny seed has only got a tiny amount of food inside to use to germinate and push the first leaves above the soil.  If planted too deeply, it will simply run out of food before the little seedling can reach the surface.

Other common causes of seeds not germinating are - the seed is too old, the temperature is not right, or they did not receive enough water and the seed dried out.  Some seeds require further coaxing to come out of dormancy and germinate.   Before planting they may require soaking, scarification (scratching the seed coat), or stratification (refrigerating seeds).  So read the seed packet instructions on SOWING prior to planting, but don't follow the instructions on WHEN to plant, as it usually doesn't apply to Arizona.  Here is an Arizona Seed Starting Calendar:

Another great Arizona planting calendar is available at Greg Peterson's Urban Farm.

As for when to start herbs from seed, the best reference guide is the awesome Arizona Herb Association's book "The Low Desert Herb Gardening Handbook" -


Another great resource is The Herb Lady Catherine Crowley's book "Edible Landscaping in the Desert Southwest".  Catherine include's an extensive list of edible flowers in her book.  I knew that naturtium, calendula, and dandelion flowers were edible, but did you know that yucca flowers, carnations, and okra flowers are edible?

If you really want to learn more about growing herbs and edible flowers, come on out this Saturday, February 3rd to the Master Gardener Demonstration Garden from 8am to 12pm.  The Arizona Herb Association has herbs and flowers growing all around the perimeter of the demonstration garden and need volunteers to come and help tend to the plants. You can also volunteer to help in the Master Gardener Demonstration Garden every Tuesday from 3pm to 6:30pm.  Location: Maricopa County Cooperative Extension, 4341 E Broadway Rd, Tempe, AZ 85040

Master Gardener Demonstration Garden

These are great opportunities to meet other desert gardeners, get hands-on experience, get questions answered by Master Gardeners, Herbies, and other experienced and dedicated gardeners.  You might even go home with a few seeds and volunteer seedlings!