What to Plant in Fall in San Diego: Flowers and Soil-Building Cover Crops
Fall in San Diego may not bring crisp leaves and frosty mornings, but it does bring something gardeners can get excited about: a fresh chance to plant and prepare for next year.
During fall, we get the opportunity to put down roots, build better soil, and get ready for the blooms ahead. At Native Poppy, we have a small urban flower farm of our own, where our team grows many of the locally-grown blooms that you’ll find in our shops. We got the chance to catch up with our farm team, Jesse and Margaret, to dig into what to plant in fall, how to care for your soil, and how the work you do now can set your garden up for the seasons ahead.
The Big Picture: What Happens in the Fall
For Jesse and Margaret, fall isn’t simply the end of the growing season. It’s the time of year to slow down, restore the garden, reflect on the year, and prepare for 2027.
Jesse, when you think about fall, what does this season mean for the garden?
“Fall at the garden means early mornings, hot days and sunsets creeping earlier & earlier. As the daylight hours shorten, we start putting the season’s beds to rest. After the last flush of dahlias, we’ll cut the plants back. Some tubers can overwinter—meaning they stay tucked safely in the ground until they sprout again next spring—while others we’ll dig up, divide and store before replanting. We’ll also plant some cover crops to add organic matter and keep that soil biology buzzing.”
Margaret, is fall a planting season, harvesting season, planning season, or a combination of all three?
“All three! Fall is the most restorative season in the garden, we’re still planting cover crops as well as winter & spring crops. Harvests are majorly slowing but we keep cutting as long as the garden will give while we also yield time for flipping and revitalizing the beds for next season. It is the biggest planning season of all as we have the time to reflect on the year thus far and plan how to make the next year our best yet.”
What are you two paying the most attention to right now as you prepare the garden for winter and spring?
“Without the weekly busy work of planting, weeding, harvesting, & deadheading, we’re able to make some big fixes to our farm irrigation and improve our shade cloth structures. We can build out more netting to support our crops.
We are really trying to dial in our succession planting schedule to operate the farm in the leanest manner, always striving to work smarter not harder. As the saying goes about business, it's our time to work on our farm, not in our farm.”
Fall Preparation: Soil Health + Organic Matter
Fall is also an important time to think beyond what’s blooming above ground. For a healthy San Diego flower garden, the soil needs care, too. Building organic matter is one of the ways our team prepares our beds for future crops.
Jesse and Margaret are big on a healthy garden eco-system, noting that, “When you continually grow flowers in the same space without giving it time to recover, it takes its toll. Over time, it will deplete the soil. The soil feeds the plants and needs to eat too!”
When you talk about building organic matter in the soil, what does that actually mean?
“Usually that means adding a couple inches of compost to every bed. It means our soil will have better water retention, that the bacteria, fungi and worms that are the soil ecosystem that feeds our plants have the food they need to nourish our crops. It means growing cover crops that can pull nitrogen out of the air and put it into our soil.”
Fall Planting
What is something about fall gardening in San Diego that might surprise someone who is used to maintaining their garden in other parts of the country?
“Gardens are commonly planned for the year according to first and last frost dates. In east county, we’re lucky if we get one or two soft frosts and almost never any hard frosts!” Says Margaret, who knows this well after five full seasons at our flower farm. “Planning looks a lot different for us and even though we have a temperate enough climate to grow all year round, the short days affect the ability of the garden to be as productive as other times of the year.”
And while fall may signal cooler temperatures and the end of the growing season in other parts of the country, September and October in San Diego can still bring plenty of heat. That means gardeners are balancing shorter days with temperatures that can feel more like summer.
When it comes to what to plant in fall in San Diego, what flowers are you planting now to grow through the cooler months and into winter/spring 2027?
“Celosia, Bells of Ireland, Ranunculus (Butterfly too), Anemones, Sweet Peas, Stock, Snapdragons, Bachelor Buttons (Romantic Variety) are coming soon!”
Jesse shares with us excitedly, “We have to wait out the heat a bit but also get a jump on cool season crops particularly those that we have to pre-sprout (anemones & ranunculus) or grow cold & mimic a “chill” period (sweet peas).”
Cover Crops
If you’re new to gardening or have never considered planting something specifically for your soil, cover crops are worth getting to know. They’re an important part of the farm’s fall routine and can be useful for home gardeners, too.
Margaret, for someone who has never heard the term “cover crop,” what does it mean?
“A cover crop is an in-between crop, between the intensive production and harvests of the year to restore the soil biology and add organic matter to the beds.
Cover crops can have different purposes - legumes for instance literally pull nitrogen from the atmosphere and put it to the soil to make it bioavailable for the next round of crops. Other cover crops we grow to invite beneficial insects to the garden. Some crops, like Phacelia and Buckwheat, we can even entertain growing for cuts and cover.”
Could a home gardener use cover crops in a small backyard garden, or is this primarily a farming technique, Jesse?
“Although more intensive than the average backyard garden, our farm is essentially a front yard garden! It is a technique serious farmers use for increased yields, but backyard gardeners can certainly plant cover crops to improve the health of their gardens too!”
Fall Flower Harvests
In addition to planting, there is still plenty to cut and enjoy! Among florists, flower farmers, and flower lovers alike, there is much spirited debate about the best season for floral harvests - spring or summer. Frankly - we can’t decide - but seeing what’s coming in from our garden right now might just tip the scale.
Which flowers are you each most excited to grow and harvest?
“Dahlias and Foxglove, Dianthus and Amaranthus, Celosia, Zinnias, Hypericum, bits and bops of Chantilly Snaps and Cupcake Cosmos.”
Jesse shares that, “For fall, I’m forever a dahlia babe with a side of foxglove fever. I also love seeing our Chantilly snaps come into their own, and everybody knows I’ll always have a soft spot for a good bed of strawflowers. One of the fun challenges of our small-scale urban flower farm is figuring out which flowers really thrive in our unique growing setup, and then leaning into the ones that do.”
Margaret shares that, "Dahlias are pure magic as the nights cool and the days get shorter, the pigmentation of their blooms get actually gets more intense so it's hard to call any other flower my favorite of the fall but the autumn tones of hot biscuits amaranths warm my wishes for sweater weather and theres something about the flamingo feather celosia that just carries me through when I'm ready to call it but the garden keeps giving."
"Pre-sprouting anemone & ranunculus corms is such a joy. I could go down a whole rabbit hole on why I love planting the winter/spring stuff like corms and sweet peas but maybe we'll save that for another blog."
Margaret, after growing flowers for five full seasons, can you and Jesse share which blooms perform especially well in the fall, and what makes them successful?
“Our most productive and favorite crops this year have to be dahlias and foxglove. We’re leaning into varieties that we know thrive in our small but mighty flower farm, and dedicating more time to deadheading and crop care throughout the season," says Jesse.
"We plant many varieties of dahlias but 'salmon runner' is running to the top of our list for farm favorite. We tend to grow Dalmatian foxglove varieties in many colors, which if planted at the right time are first year flowering letting us treat these typical biennials as an annual crop. Dalmatian peach is our fav," says Margaret.
Making the Most of Fall
After hearing from Jesse and Margaret, one thing is clear: fall in the garden is anything but a quiet season. From tending the soil and planting for spring to harvesting the blooms that are still putting on a show, there’s plenty happening beneath and above the soil.
Fall may mean slowing down for some, but there’s lots to do in the garden. There are cool-season flowers to get in the ground, soil to feed, and a few more blooms to soak up before the season turns.
Want to hear more from Margaret and the growth of our urban flower farm? Read more in this post. Want a piece of the locally-grown floral magic at home? There’s still time to scoop up the last of the season’s harvest from our garden, along with beautiful blooms from our local flower farm partners on our San Diego Grown flower menu!
