September 22, 2012

1 - Things gardeners should be doing in the autumn to prepare for spring.

Yard and Garden September 22, 2012


You have written recently about planting trees, shrubs, flowers, and vegetables in the autumn. Are there other things gardeners should be doing in the autumn to prepare for spring? Should we do anything to the soil? Is there anything else?

- Gail

Silver City


Autumn is a good time for doing many things. The hottest part of the year is past, we are busy harvesting vegetables and enjoying flowers from the garden, and we should be thinking about winter and next spring.

Diagram your garden to identify where various crops were grown this year (and last year if you remember). This will help you avoid planting the same crops in the same places next year. Rotating crops helps avoid build-up of diseases in the soil and helps to diversify nutrient usage since different crops use different nutrients in the soil.

If you have not had your soil tested recently, collect a soil sample and send it to a soil testing laboratory. This will help you apply nutrients for your crops next year. Your local NMSU Cooperative Extension office can provide you with information regarding soil testing and can help you understand the soil test results. Collecting the sample from warm soil in the autumn will result in more accurate results and give you more time to evaluate and implement the recommendations than if you collect the sample in the early spring.

Some areas of New Mexico should begin disconnecting the garden hoses from the outdoor taps now. Even though the garden may still need irrigation, freezing nights can result in broken pipes if the garden hoses are left attached to the taps. They may be reconnected during the day and disconnected again at night. This process may be delayed in warmer parts of the state.

The soil may be tilled now and organic matter incorporated into the soil. If manure is to be worked into the soil, this should be done in the autumn to allow time for excess salts to leach into the soil and prevent burning of plants in the spring. Compost may also be incorporated in the autumn.

As garden plants die, gardeners can collect the debris to add to their compost piles. Traditional wisdom says to avoid adding to the compost pile weeds that have set seeds and diseased plants. If you are not sure if the plants should not be added to the compost, a way to reduce problems is to place questionable plant material into a black plastic bag with water, set this in a sunny area and let the heat from the sun pasteurize the plant debris before adding it to the compost pile. The temperature of material in the bag should reach 130 to 160 degrees to be sure any weed seeds and disease organisms have been killed before adding it to the compost. The material will have begun the composting process during this treatment, so it will also help speed composting.

Some gardeners make compost directly in the garden by digging deep post-holes and pouring kitchen wastes into those holes. Cover this material with at least a foot of soil to keep animals from digging in the garden and be sure to water these compost-holes when the soil is dry to encourage the composting organisms to decompose this material before spring gardening begins. In areas where the ground freezes, it may be wise to prepare the post-holes ahead of time so that they may be filled when the ground is frozen in the winter. Keep some thawed soil available for covering the compost during the winter. Cover the open holes for safety until they have been filled and covered with soil. In the spring, when tilling the garden, the material composted in the garden will be mixed with soil in the tilling process.

Now is the time to order garden catalogs. Later fall and early winter, when it is cold outside, is a good time to peruse the catalogs and place your orders so that seeds and plants will arrive at the proper time for planting in your area. Ordering the catalogs early allows plenty of time for the catalogs to arrive. It is possible to peruse garden seeds and plants on the internet as well.

Finally, do not forget to begin preparing houseplants for their return to their indoor, winter locations. Begin inspecting carefully for insects and diseases. Propagate from cuttings or seeds plants that have become too large or unattractive. Repot those plants that have been in their pots too long, or if salts have been accumulating from irrigation water.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!