June is the month when Riverside gardens make a dramatic shift. Cool-season crops that thrived through winter and spring are beginning to struggle as temperatures warm up, while warm-season vegetables are finally hitting their stride. If your lettuce is suddenly shooting up flower stalks, your cilantro is blooming, or your spinach is turning bitter — don't worry, you aren't doing something wrong. That's exactly what should be happening this time of year.
This is also the month when tomatoes begin to set heavy fruit, peppers start growing rapidly, and squash plants seem to double in size overnight. If we hit a sudden stretch of high temperatures, deep watering may be necessary. A well-watered garden handles heat far better than a thirsty one. Check your irrigation system now, before the hottest part of summer arrives.
If you're harvesting more zucchini than your family and neighbors can eat, try shredding and freezing it for future zucchini bread or muffins.
What Are We Picking?
Vegetables: Lettuce, kale, Swiss chard, cucumbers, beets, radishes, green onions, zucchini, summer squash, cherry tomatoes
Herbs: Rosemary, thyme, oregano, basil, parsley, sage
Flowers: Zinnias, cosmos, sunflowers, marigolds, lavender, yarrow, daisies
Fruits: Strawberries, early figs, lemons, limes, blackberries, raspberries
Normally, early peaches, nectarines, and apricots would be ready for picking this time of year. However, after the warm winter we experienced, many trees didn't receive enough chill hours to bloom properly. No blooms means little to no fruit production this season. If your stone fruit trees are loaded this summer, consider yourself fortunate — many gardeners across our area won't be harvesting peaches, nectarines, plums, or apricots this year.
What Are We Planting?
June is all about warm-season crops. Soil temperatures are warm, nights are mild, and heat-loving vegetables will establish quickly. Focus on plants that thrive through Riverside's summer heat.
Plant now: Tomatoes (transplants), peppers (transplants), eggplant (transplants), basil, cucumbers, zucchini, summer squash, pumpkins, melons, beans, sweet potatoes, sunflowers, zinnias, and heat-tolerant herbs.
If you have empty space from harvested spring crops, don't leave bare soil exposed — that only invites weeds. Instead, add compost and immediately replant with a summer crop. Bush beans are an easy option.
Want to try something new this year? Grow your own loofah sponge! They grow on a vine, so you'll need plenty of space, but the plants are beautiful, the flowers are large and yellow, and at the end of the season you'll have real sponges to use in the shower. It's a conversation starter and a garden project all in one.
What to Watch Out For
Spider Mites: As temperatures rise, spider mites become active on tomatoes, beans, cucumbers, and many ornamentals. Leaves develop tiny yellow speckles, and you may notice fine webbing with tiny red bugs covering your plants. Solution:Spray leaf undersides with a strong stream of water several times per week, and avoid letting plants become drought-stressed.
Leaf-Footed Bugs: These pests damage tomatoes, peppers, pomegranates, squash, and other fruits and vegetables by piercing them with their needle-like mouths and sucking out the juices. Their feeding causes discoloration, scarring, and misshapen fruit. Solution: Hand-pick adults, remove clusters of bright red-orange nymphs before they mature, and introduce beneficial insects that attack their eggs. Catching them early is key.
Tomato Blossom End Rot: You may notice dark, sunken spots forming on the bottoms of developing tomatoes. This is usually caused by inconsistent watering rather than disease. Solution: Water deeply and consistently, and mulch around plants to help maintain even soil moisture.
Squash Vine Borers: Squash plants may suddenly wilt even when the soil is moist. Check stems near the base for small entry holes. Solution: Inspect plants regularly, remove affected portions if caught early, and consider covering young plants with insect netting until flowering begins.
Gardener's To-Do List
- Remove bolting lettuce, cilantro, and other cool-season crops to make room for summer vegetables.
- Add 1–2 inches of compost to harvested beds before replanting with warm-season crops.
- Inspect irrigation systems weekly and adjust watering schedules as temperatures increase.
- Mulch vegetable beds with 2–3 inches of straw, wood chips, or shredded leaves to reduce evaporation and suppress weeds.
- Support heavy tomato growth by tying plants to stakes or cages before branches become loaded with fruit.
- Harvest zucchini, cucumbers, and beans regularly to encourage continued production throughout summer.
Closing Tip
One of Riverside's greatest gardening advantages is our exceptionally long growing season. While much of the country is just getting started, we're already harvesting and planting at the same time. If you missed planting your garden this spring, you're in luck — it's not too late! Focus on what grows well in the season you're in. As we head into the hottest part of the year, now is the perfect time to plant heat-loving crops like tomatoes, peppers, squash, cucumbers, melons, and beans. Take advantage of every empty space and keep something growing year-round.
Pro tip: Before the first major heat wave arrives, add mulch to every garden bed. It's one of the simplest things you can do to reduce watering needs, protect soil life, and keep plants productive through summer.
More information: Kim Malstrom designs, installs, and teaches vegetable gardens for beginners and families in Riverside. To learn more, visit kitchengardensbykim.comor follow along on Instagram at @kitchengardensbykim.
