Southern California Gardener's September Checklist

September in Southern California is a transition from summertime to springlike weather warm days, crisp nights along with a chance of hot, dry Santa Ana winds. Over the next few months, we’ll observe the shift at local nurseries from summer bloomers to winter flowering plants and out of hot season veggies to cool season types.

While October is prime planting season, September is best spent cleaning out the old, preparing the soil and planning your autumn garden.

This month look for fall-planted, spring-blooming bulbs, such as daffodils, narcissus, tulips, hyacinth, bearded iris, crocus, allium, ixia and daffodils. Stock up on seeds of cool season veggies and annuals — like sweet peas, nasturtium and wildflowers — so you are all set to get them in the ground whenever the heat subsides. You will also want to hit the books, catalogs and Web for ideas.

First, check out these hints, and happy September digging!

Turn, water, wait, bud: A simplified mantra for prepping a new garden bed.

Soil prep. A terrific garden starts with good dirt: Do not skimp on this vital task. The objective of soil preparation and amendment is to create a healthy soil microbial suite — the microflora and microfauna that are essential to breaking down organic substance that other soil fauna and flora convert to soluble plant nutrients. (Ironically, this can be an over-simplification of this process. The purpose is, be good to your soil, and it’s going to be good for you.)

Soil prep will depend on what you are planting.
Natives and Mediterranean plants. These need little soil prep. Most are adapted to lean soils (low organic content, low nutrients). Trees, shrubs and perennials. Limit soil amendment to the planting hole , and depart surrounding soil undisturbed. A heavy layer of mulch around the new plant and adjacent soil will provide what’s needed for a healthy soil microbial suite. Annuals and veggies. Prepare an whole bed or area to provide the organic-rich, well-draining dirt these plants need. New beds: Let us assume you are just getting started and you would like beds ready for planting now. To prepare a fresh mattress, remove unwanted plant material (weeds, sod, etc.), turn the soil and water thoroughly. Keep on watering for at least two weeks, letting weed seeds to germinate. Yank those weed-lets and you are ready to move.

How to Acquire the Weed War


Adding nutrients: Now is the time to add nutrients to the beds you intend to plant when the weather cools. Compost existing beds. For new beds, then include compost, N-P-K (see below), trace elements and gypsum (for tacky clay soils) and turn everything in.

Bed prep: I like to include three to four inches of organic substance, such as compost or planting mix . For heavy, sticky clay soil, add a few agricultural gypsum at this point to help break this up. Scatter slow-acting, very low focus N-P-K and follow nutrients on shirt and then give it all a fantastic blend with a rototiller or a spoonful. Compost made of mixed materials like green waste, egg shells, coffee grounds and other kitchen waste normally contains all the necessary nutrients for healthy growth. If you don’t have yummy homemade compost, then add individual ingredients to your mix, following label instructions. You’ve got lots of choices; here are Only a few to pay the N-P-K:For nitrogen (“N”): bloodmeal, cottonseed meal, or well-composted manureFor phosporus (“P”): bone mealFor potassium (“K”): kelp meal, wood ash

Robin Amorello, CKD CAPS – Atmoscaper Design

Select Cool Season Veggies

Plant cool season veggies — primarily those developed for their leaf, root or tender seed pods — toward the end of September in Southern California.

Jocelyn H. Chilvers

Root plants. Select radishes, carrots, turnips, beets, potatoes and other edible roots. Plant them straight in the ground whenever the heat subsides.

Jocelyn H. Chilvers

Leafy veggies. Search for types of cabbage, broccoli, cauliflower, kale, brussels sprouts, chard, lettuce along with many others. Get them at the ground whenever the scorching days have passed.

Robin Amorello, CKD CAPS – Atmoscaper Design

Peas, please. Time to plant peas, too: snow, snap and English. Keep in mind that English peas will need to be shelled; the other two are consumed pods and all.

Cool-season Crops to Increase in Fall


Cool season blossoms. Search for these to sow this month once things cool down:’Bachelor Buttons’, calendula, black-eyed susan, coreopsis, wildflowers, nasturtium and sweet peas. Plant”ancient flowering” types of sweet peas now, and you’re going to have them by December.


Outdoor Garden Trellis

Add trellises now for winter structure and color. For your climbing veggies and flowers, spice it up this year and go for something vibrant and striking.

Barbara Pintozzi

Split bulbs. It’s time to dig and divide’Naked Ladies’ (Amaryllis) along with other autumn bulbs that have become crowded. Lift, divide and replant after the bloom is completed but before the leaves appear.

Plant fall bulbs. Search for daffodils, anemone, ixia, dahlia (LOVE the dinner plate dahlias), calla lilies, iris, babiana, watsonia, freesias, ranunculus, muscari and lilies. Get them at the ground as soon as they arrive in your regional nursery or via mail order.

6 Unsung Bulbs for Fall Planting

Attempt some chemistry in the backyard. If you are up for a small horticultural fun this month, try messing with the color of your hydrangeas. Start before new buds develop, shifting soil chemistry to enhance the blue at the blooms of pink- and – blue-flowering varieties. (The trick doesn’t utilize white-bloomed varieties.)

It is possible to alter the color of hydrangea blossom heads (which are actually bracts) by changing the pH of the ground. For blue blossoms, you are going to want to achieve a pH of 4.5 to 5.5. For pink blossoms, you want a pH of 7.0 to 7.5. Use an inexpensive soil pH test kit from the nursery or hardware store to check the pH of the soil around the plant’s roots. Reduce the soil pH by adding sulphur or aluminum sulfate (making the soil more acid). Boost the soil pH by adding ground agricultural limestone (making the soil more alkaline). Follow label instructions for application rate and frequency.


Water citrus. Water citrus trees deeply and uniformly while the heat is still on. Dry roots lead in fruit.

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