Still Time to Plant Summer Vegetables!

By Susanne von Rosenberg, UC Master Gardener of Napa County

For me, this past year has been very distracting, so I'm not as far along with planting my summer garden as I normally would be. If you can relate, the good news is that it's not too late to have a successful summer vegetable garden.

Even if you already have your summer vegetables in, you may be thinking about other crops that you would like to grow. Early June is still a great time to plant tomatoes (except beefsteak types, which take much longer to reach maturity), peppers, eggplants, beans, chard, cucumbers, melons, squash and pumpkins. Because you're planting later, focus on varieties that require fewer days to maturity.

This year, because of the drought, I would avoid planting corn as well as watermelons. Both require a lot of water to yield well and only produce a small harvest for the space required.

One vegetable that you can plant now for a successful fall harvest may surprise you: potatoes. If you plant short-season (early) potatoes, you can plant as late as the middle of July for a harvest by mid- to late October.

Some gardeners also like to plant a second round of cucumbers in mid- to late June to have more crop when the harvest from their initial planting tails off. If you typically plant bush beans, additional sowings will extend your harvest into early fall. (If you plant pole beans, just keep them picked to keep the vines productive.)

So how do you figure out if it's too late to plant a vegetable you wish you had planted weeks ago? You need to find out the days to maturity for the vegetables you have in mind.

Days to maturity are typically figured from date of planting (if planted from seed) or from date of transplant for seedlings. Once you know the starting point, you can simply count from there to the expected harvest date…kind of.

Days to maturity listed on a seed packet or plant tag are usually best-case scenarios. In my experience, my plants never meet the expected days to maturity. Assuming you also do not have the absolute ideal conditions, your vegetables will take a little longer to mature, so give yourself a cushion of a couple of weeks or more. I've noticed that different catalogs differ in their days to maturity by as much as 10 to 15 days, so I know that this figure is truly an estimate.

Remember also that days get shorter after the summer solstice (June 20 this year), so plants will grow more slowly after that. If you are buying a seedling with no stated days to maturity, look it up online or choose a different variety. Days to maturity can vary by weeks. For example, Yellow Doll watermelon is listed as requiring 65 to 70 days to maturity, whereas Carolina Grey may take up to 100.

If a vegetable variety is labeled as “early season” or “short season,” it's usually a good bet for last-minute planting. Also, the larger the vegetable or fruit, the longer it typically requires to ripen. It simply takes more energy to produce the sugars and starches that go into a larger vegetable or fruit.

What if you've already planted your garden but just wish you could plant a few more things? Or what if you miss your spring lettuces or Asian greens?

Growing vegetables in containers can expand your garden's capacity as well as your planting options. Containers allow you to take advantage of microclimates in your yard. If you're missing the vegetables that normally grow in the spring and fall, you may be able to grow them in the summer in a shadier, cooler location in your yard, such as on the north side of your house or in the dappled shade under a tree.

The only way to really know if this approach will work in your yard is to try it. In general, plan on harvesting summer-grown greens when they're fairly young; hot weather can cause them to develop strong or bitter flavors. If you're going to plant in containers, check out the Master Gardeners' Healthy Garden Tips for information on how to do so successfully.

Free Guided Tree Walk: Join Master Gardeners of Napa County for a tree walk in Fuller Park in Napa on Tuesday, June 8, from 10 a.m. to noon. Limited to 12 people per walk. COVID safety protocols will be followed. You will be asked health questions and asked to sign in. Face masks and social distancing are required. Register here.

Workshop: UC Master Gardeners of Napa County will lead a free workshop on “Worm Composting” on Saturday, June 12, from 10 am to noon, via Zoom.

Learn how to turn your kitchen scraps into rich compost with red worms. All attendees will receive all the materials necessary to make a worm compost bin at home. Pick-up arrangements will be made after you register; limit one bin per family. Register for "Worm Composting with Penny" at City of Napa Home Composting Workshops 

Workshop: UC Master Gardeners of Napa County will lead a free workshop on “Summer Rose Care” on Saturday, June 12, from 10 am to noon, via Zoom. Register at http://ucanr.edu/2021SummerRoseCare

Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.

For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.