Here is a proposed Six Season Calendar for the California Natural Garden:
Pre-Fall – September – Bye bye hot and dry, hello cool and moist, transition month.
Fall – October, November – many garden tasks, planting season begins, fall flowers.
Winter – December, January – enjoy the short days, migratory birds, bundle up, pray for rain.
Spring – February, March, April – enjoy abundant flowers, birds, butterflies, life!, good planting season.
Pre-Summer – May – Bye bye cool and moist, hello hot and dry, transition month.
Summer – June, July, August – enjoy the long days, judicious watering, summer bloom.
The daylight hours are notably shorter and plants are readying themselves for the rainy season still two months away. Cooler nights, shorter days, and cooler soil temps mean less stress on the plants, especially in the leaves where water is lost through transpiration. Summer 2018 was particularly brutal, so many plants may still have burned leaves (from July 6) or are still struggling to stay alive. Evaluate your whole garden on a plant by plant basis.
September and October can produce some very high temperatures, drying Santa Ana winds, very low humidity. These fall heat waves usually only last a few days when they come, and the fall nights will be cooler. Be ready for hot dry spells this month. Continue your summer watering patterns… “deep soak” with an irrigation event every 3-4 weeks and “refreshing sprinkles” about twice a week. Look for ideal times to apply water: cool spells, cool mornings with marine layer present, cool evenings with a breeze, cool days. Stay cool. Never water in the heat of the day. Try to soak your ground thoroughly ahead of a heat wave. Watch the forecasts, apply water when it is not blazing hot.
It bears repeating every month in summer, including September (Pre-fall)… One deep soak every 3-4 weeks May through October, light refreshing sprinkles in between. “Deep soak” means you run the sprinkler or hose end sprinkler about 30 minutes a day, three days in a row (total 90 minutes) in early mornings to thoroughly soak all the ground applying approx. 1.5” precipitation. “Refreshing sprinkle” in late afternoon or early evening means run the sprinkler 3-5 minutes, about 2-3 times a week… enough to wet and cool the leaves and cool the soil surface at the end of the day. Deep soak is an irrigation event. Refreshing sprinkle is not. For more detail see http://californianativeplants.com/wateringnativeplants
Irrigation event = deep soak, 1.5”+ precipitation by watering. Usually you have to run the sprinklers three days in a row, very early morning for 20-40 minutes each day for a cumulative run time of 1.5 to 2+ hours, and a cumulative amount totaling 1.5”+ of water in your garden. It’s like three days of rain showers. You do this about every three or four weeks May through October, during cool spells in anticipation of heat events.
Refreshing sprinkle = 5 minutes or less of sprinkler or you holding the hose with a spray nozzle, to cool the plants and the soil, wash off the leaves and freshen things up. This can be done a couple times a week or so, and always in the late afternoon or early evening. You barely get the surface of the soil wet. The plants love it.
To achieve the most success, you have to do both, “irrigation event” and “refreshing sprinkle.”
Related to Watering
Weather in September can be tricky. Be sure to catch up on all the details regarding summer watering by looking up a few of our past newsletters. Read the June, July, and August in the Natural Garden posts, and assimilate the information into “pre-fall” September. With the meager rains from last year, many landscape soils are still lacking their commonly present deep moisture we normally take for granted. Assuming you have supplied your garden with deep irrigation throughout the 2017/18 dry season, know this: the quality of your irrigation water has not been good. Our imported municipal water is high in dissolved salts, especially that from our summertime sources. For this reason, when you water deeply in September, try to leach the salts down, because during the summer they have invariably risen to near the surface during the evaporation process. And pray for rain, the best quality water we’ll ever get.
As a general rule we do no major pruning in September. Desert trees, (palo verde, mesquite, desert willow, sweet acacia) should be thinned and headed back, as they will keep growing during the remaining weeks of warm weather. Break off any sunburnt branch tips on manzanita, ceanothus, etc. You can remove unsightly dry flower heads. Many people leave the brown seed heads of buckwheat on the plant. Next month, or even in late September, you can thin and shape native plants.
Don’t let summer weeds go to seed. Use a hoe and haul the cut weeds away.
Be patient. Encourage natural mulch (leaf fall from your plants). If your garden looks good with a few patches of bare dirt here and there, you’re fine. You can also move natural mulch from one spot where it might be thick to any other spots where it is thin.
We recommend organic fertilizers, if applied as granular or dry product, scratched into the top 2” of soil with a three-prong cultivator. Towards the end of the month, just before what might be your last irrigation event of the summer, you can make your first application of plant food. Choose one with a low N-P-K (the three numbers on the bag) like 5-3-1. Most balanced plant foods also contain micronutrients like iron. This can wait until October. No rush, but if you do it in late September, water thoroughly right away.
Troubleshooting – Varmints, Pests and Diseases
Look for ants’ nests and try flooding them into oblivion with a steady stream of H20. You’ll get some deep hand watering accomplished in the process. Plant diseases, especially root and crown rot will still be a factor if you are watering too frequently or too close to the plant’s crown. A long as soil temps are in the mid 70’s (they still are) root rot fungi can be active. This is why you are to water on cool mornings.
If we start cooling off mid month, you can sow the seed you have been waiting all year to sow, and initiate germination with sprinkler water. The best approach would be to sow seed at the onset of the cool season rains.
Adding New Plants
Yes, yes and yes. Starting September 15 you can plant safely… close enough to textbook safe planting month, “October.”
You made it. We made it. Summer 2018, with seemingly never ending scorching heat and wildfires, will soon give up the ghost and be reborn into fall. The long hot days are fading.
Find the most aromatic plants you can, sage, yerba buena, wooly blue curls, coyote mint, desert lavender, etc., and make your own Pre-fall Refresher. Arrange the stems and blooms in a vase for indoors. Dry some leaves and stems for winter pot-pourri. Float some sprigs of yerba buena or wooly blue curls in ice water for a toast to summer’s end. And don’t forget to dream about all those new plants and new details you’ll be adding to your natural garden next month. We made it. In the garden, life starts to get a little easier about now.
From the Garden,
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