Basil, Basil, Basil!

I sometimes think that when I’m older, I’ll live in a condo or apartment so I can do other things besides tend a huge garden, like finally go kayaking or maybe relearn all that Spanish I once knew, but have long ago forgotten. I would miss gardening, but I think I would be all right as long as I could grow Sweet Genovese basil somewhere. I grow a lot of herbs, but none give me the same life-is-good feeling I get when I go out and snip a few basil leaves for an omelette or pizza. Lots of other people feel the same way, I know, because when something goes wrong with basil, they really freak out. And who can blame them? Minnesota summers are short, so if the basil you’ve been lovingly tending goes south, that’s it for the year. So here comes the good and bad news—bad news first so you won’t go away droopy.

Genovese basil used to thrive until fall before basil downy mildew came along.

Lately, I’ve been hearing a lot of this question: “My basil was doing so great, and then it turned all yellow and got brown spots all over it. What happened?” If this is happening at your house too, the problem is probably basil downy mildew. Caused by a water mold that thrives in warm, humid conditions, this basil-ruining mildew was first found in Minnesota in 2012 and has been making homemade pesto nearly impossible ever since.

Other issues can resemble basil downy mildew, but if you see plant leaves turn yellow, get brown and/or black spots and maybe even start falling off, you can pretty much bet that’s what you’re dealing with. Once a plant is infected, pluck off any leaves that still look decent and chuck the rest in your yard waste can or bag. Because the pathogen that causes this disease can’t survive our Minnesota winters, it is safe to throw it in your compost bin if you have one. Just be sure to bury it a bit because spores can blow to nearby plants.

Before the brown spots appear, plants just look a bit yellow, which can be mistaken for nutrient deficiency.

One of the best ways to avoid this disease next year is to buy basil seedlings and/or seeds from someone you trust to manage their plants well. Too often, plants and seeds are already infected with basil downy mildew when we buy them: it just hasn’t started to show yet. I like to buy my basil seedlings, and other vegetable and herb plants, from Dehn’s Garden. The family-owned farm has been a regular at the Minneapolis Farmers Market for more than 30 years and I have never had a problem with basil I’ve bought from them. (This isn’t to say that it couldn’t happen, though, because spores can still blow around and infect plants.)

While we can’t do much about what the wind drags in, there are some things gardeners can do to try to keep basil downy mildew at bay. Rather than using an overhead sprinkler or sprayer, water the soil beneath basil plants by hand to help keep leaves dry. Also, make sure plants have good airflow around them by thinning out overcrowded beds and containers and keeping weeds pulled. Better still, do as I do and plant way more basil than you’ll ever need. That way, if some plants get infected, you’ll still have plenty more. If all of them do well and stay healthy, you can make pesto for everybody and they will love you!

Tasty Pesto Recipe

Well, it’s definitely good news that you don’t need a lot of basil to make a delicious batch of pesto. So feel free to adjust this recipe according to the amount of leaves you’ve gathered up.

• 2 cups fresh basil leaves (I like Sweet Genovese.)
• 3 cloves fresh garlic
• ¼ cup pine nuts or walnuts (optional)
• ¾ cup organic, extra-virgin olive oil
• ½ tsp salt and ¼ to ½ tsp pepper
• ½ cup grated parmesan cheese

Combine basil, garlic, nuts, salt and pepper and HALF of the olive oil in a food processor or blender. Blend on a low speed as you add the rest of the oil. Scoop the mixture out into a large bowl and stir in the grated cheese. And, voilà! Pesto is best eaten the same day it’s made, and it will turn brown if left exposed to air very long. If you decide to freeze some, I find it works best to leave out the cheese, which you can add when you thaw out your pesto for a meal. Enjoy.