August in zones 9 and 10 is one of the hottest months of the year where even night-time lows rarely drop below 70 degrees. It’s a time when summer crops are really starting to show their age and resilience to disease, pest pressure, and the rising temps are waning.
Even though it can be sad to see the garden turn from a lush green paradise into a less-than-attractive heap of browning and diseased foliage, there is plenty to plant and plenty to plan for!
So, if you have wondered what to plant in August in San Diego or other areas in zones 9 and 10, then you’re in the right place.
What to Plant in August – Zones 9 & 10
August is a pretty exciting month for us in zones 9 and 10 because it marks the beginning of Fall planting.
Things are looking pretty rough this time of year, and it’s certainly refreshing to know that the garden will once again look lush and green in the coming weeks ahead.
While it may seem exhausting to yet again start a bunch of seedlings for an abundant Fall harvest, I promise that all your efforts will be rewarded when you harvest that first perfect head of cabbage, more broccoli than you know what to do with, and perhaps even a gorgeous crown of purple cauliflower.
This is the time of year to dream of cold weather crops and get them started before the daylight hours become too short.
So, let’s get into what to plant in August in Southern California.
What Veggies to Plant in August - Zones 9 and 10
While the harvests from your summer bounty start to die down (quite literally), it’s time to start thinking about those wonderful cruciferous veggies.
These beauties, while obviously cool-weather crops, actually need to be started when the days are still warm and long.
This can be a bit tricky in zones 9 and 10 since we technically have another two months of “summer” weather ahead. However, the daylight hours are getting shorter by the day. This means we need to get seeds started and transitioned outdoors before daylight hours become too short to produce sizeable crops.
If you start seeds too late, your crops won’t get the warm and daylight hours they need and might end up stunted and leggy. This can waste a ton of time since there’s a high chance that leggy starts won’t produce well and even succumb to early disease and pest pressure.
If you notice this happening, restart some seedlings as a backup to help ensure a robust outcome.
Also note that you should keep plenty of space available for your Fall varieties as you pull spent summer crops from the garden.
This includes thinking even further ahead and saving space for things like garlic and onions come October.
Here’s a List of Vegetable You Can Plant in August
- Beans** (pole and bush)
- Brussels sprouts**
- Collard greens
- Peppers (sweet and hot)
- Sweet potatoes
- Tomatoes (cherry varieties will do best as the days get shorter)
** Means succession sow every 2-3 weeks to keep the harvests coming! This is especially great for lettuce, spinach, radishes, and beans (particularly bush beans).
Broccoli will normally produce side shoots once the main crown is harvested, but if you want more large crowns, be sure to succession plant about every 3-4 weeks. As the weather gets cooler, you may need to adjust transplanting locations to ensure adequate daylight hour exposure.
Have fun with it and get creative! Before you know it, you will know exactly where certain crops thrive in the garden during specific times of the year.
Keeping Cool Weather Seedlings Safe During Hot Weather
You can either start your seedlings indoors using a grow light and then slowly transition them outdoors, or you can start seedlings outdoors in the shade and then move them into the sun once germinated to prevent leggy starts.
Either way, once your seedlings are outdoors in full sunlight, it’s a good idea to protect them with a 40% shade cloth to help reduce the sun's intensity. You don’t want them burning or bolting prematurely! Do this until temperatures are consistently below 85 degrees.
Be sure to also keep seedlings well watered. If they dry out, you risk them becoming stunted or will lose them entirely.
What Flowers to Plant in August
- Four o'clock
- Morning glory
** Means succession sow every few weeks to keep those blooms coming.
Make sure you plant plenty of flowers and dot them around the garden to encourage pollinators to visit your crops as this can increase yields; plus, flowers just make the garden even more beautiful to look at.
What Herbs to Plant in August
** Means succession sow every few weeks to ensure a continual harvest.
Even in this heat, can still manage to find spots to tuck in a few basil plants, but it’s getting tricky. The heat makes basil bolt incredibly quickly, requiring a lot of pruning to keep the flowers at bay.
I just love basil so much that it’s a constant in the garden no matter what the weather looks like, and it has done relatively well, especially when grown next to an Oya.
As for other herbs, chives and dill are still doing great even in the heat of late summer.
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