Many perennial wildflower seeds need a period of cold, moist conditions to be convinced that winter is done and it's time to germinate. So most perennial flower seed mixes are best sown in the late fall.
Rake the soil with a stiff bow rake to clean up debris and leave behind shallow furrows to capture the seed.
Mix the seed to be sown into a bucket of slightly moist playbox sand (or arroyo/creek sand) that has been inoculated with a three or four of tablespoons of Plant Success® mycorrhizal spores. The sand helps to more evenly spread the seeds over the area to be sown and the mycorrhiza spores will germinate with the seeds and greatly improve germination , the survival of the young seedlings and hasten blooming.
If practical, mulch with a thin layer of clean wheat or barley straw or compressed, shredded wheat straw pellets (StrawNet™) to protect the seed from the wind and hold moisture needed for germination.
7. Make notes on planting for fall color next spring
The most common missing ingredient I see in American landscapes is the lack of late summer/ early fall flowers and seed heads, shrubs with colorful fall foliage and woody plants with colorful fruit to feed song birds.
This often happens because we so often do the bulk of our planting in spring and naturally bring home from the nursery lots of spring blooming plants. But by taking a look at your fall landscape, you'll quickly see where some late summer/early fall color would be a welcome improvement. And it's vitally important to provide our precious pollinators with sources of late season flowers to help them build their food stores for winter.
8. Wrap the trunks of young trees
In the sunny Western US, the winter sun can sunburn the bark of young shade, flowering and fruiting trees. This is called Southwest Winter Injury and happens when the soil is frozen and the sun heats up the southwest side of the tree's truck causing sunburn of the thin, immature bark. This is easily prevented by wrapping the trunks of your young trees with a truck diameter (caliper) of less than 3 to 4 inches. Using tree wrap, cover the bottom 4 to 5 feet of the trunk in late November and remove it in April.
9. Make compost with your tree leaves
Tree leaves are a valuable source of nutrients for feeding the soil. Instead of kicking bags of leaves to the curb for the trash collectors, shred them and use them as fertilizer or mulch. You can rent a shredder or run over small piles of leaves with your bagging lawn mower to chop the leaves into a coarse grind that's ready to use as mulch or pile to breakdown by composting. There is lots of information about composting, so study up and use your leaves; don't throw them into the landfill.
10. Collect seeds
I'm frequently asked about collecting seeds in the fall. They seem to be ripening everywhere when we look around in our gardens, fields and forests around us. It's easy and only takes some paper bags and a pair of clippers to harvest a bounty of seeds.
For many annuals and perennials, I cut the flowering stems off just above the leafy base of the plant and place the stems seed pods down into a paper grocery sack to dry and cure. Other plants, the seeds can be pulled from the stems and put into paper sacks. Once dried (it takes a week or so) the seeds can be separated from the stems or shaken from their seed pods and put into envelopes for storage. Sometimes, I just collect the stems full of seed pods and spread them out over an area of my yard where I want them to grow.
Fall is an excellent time to sow wildflowers, so these seeds can be sown as soon as you've processed and cleaned them. There are many books on seed collecting that will give you specific instructions for various species of plants. Seed collecting can be addicting and you'll find yourself doing more and more of it to provide you and your friends with a great source of new plants. So try your hand at it this fall.