DIRT NERD

SAVE THE BASIL

You want to grow basil. If you’ve never grown anything in your life, you want to grow basil. And tomatoes. You want big fat tomatoes and delicious sweet, large leaf Italian basil. Time was, you’d be totally doomed with the fat tomatoes either way; but basil, that was an herb you could get down with. Put a basil plant in a pot and feel damn good about your bright and shiny food-growing future, because that baby is popping off!

To start, let’s get one thing out of the way. It is presently December, and ostensibly a little bit cold outside. Basil is a heat-loving plant that starts to taste a little funny and shoots off flowers at the first sign of sweater weather. It’s best to grow basil in the spring and summer. Time was. These days, not so much.

There is an epidemic sweeping the nation presently. Basil is in a proper crisis. I’m not kidding; I’m not exaggerating. A disease we’d thought long gone from this land, from sea to shining sea, has returned by way of Florida and is wreaking havoc along the eastern seaboard and creeping westward as well. No, it is not Florida Man. It is downy mildew. And it’s really bad.

Downy mildew is thought to have been reintroduced to the new world vis-a-vis some shipment from somewhere in Africa to Florida in 2007. And though it remained relatively contained for a while, it has been actively decimating the commercial basil industry since 2015. It looks and acts like fungus, but is technically an algae. It thrives in warmth and especially humidity, which is why, since its escape from Florida, we feel its wrath more forcefully here in the deep south than those in northern climes do; though make no mistake, their pesto-making prowess is not nearly what it used to be.

So what does downy mildew look like? If you’ve tried to grow basil over the last few years, you probably already know. It starts off fairly unassuming: a few yellowing leaves on the outskirts of the plant that you will probably blame yourself for. Did you overwater? Under-water? Probably, but that’s not why the basil looks a little off. A week later, the yellow is everywhere, and the spots that used to be yellow are turning brown. You look at the underside of one of these sad leaves and notice brown specks dotting the thing throughout. You’ve got downy mildew, and it’s pretty much too late for you to do anything about it. But don’t be too hard on yourself: it was always going to be too late.

Seriously, sweet basil might not be a thing in a few more years. Scientists and growers are hard at work trying to make Genovese basil varieties that can withstand this all-consuming monster, but the clock is ticking. One piece of good news? You can still eat downy mildew-infested basil. It tastes fine and won’t turn you into a zombie or even make you fart (depending on what you eat it with).

There’s a little bit more good news. Though your classic pesto basil, Italian basil, sweet basil, Genovese basil—whatever you want to call it basil—is in imminent danger, some of the quirkier varieties of basil have a strong resistance to downy mildew. All your citrusy basils, and to a slightly lesser extent Thai basil, can take the wet gross heat, as it were. Supposedly lettuce leaf basil is fairly immune too, which should be great news, because it tastes just like your familiar normie basil; but I tried to grow it last year and it definitely got downy mildewed the heck up. So, I don’t know, believe the hype, or don’t.

Still want to give traditional basil growing a shot? Great. Do it. The great news? Maybe the best news I’ve got for you here today? If you fail miserably, it’s almost definitely not your fault, this time. Here’s how to maybe save your basil from being eaten alive by Earth algae so it can be eaten alive instead by Earth humans.

The first best thing you can do is start picking any iffy looking parts of your basil plants as soon as they start looking off. Any yellowing leaves, or worse, blackening leaves, should be removed immediately. Do not simply pick the leaf off, cut off the stem that that leaf is connected to. You must try hard to remove all the poison if at all possible. Unfortunately, downy mildew gets systemic pretty fast, so it might already be too late by the time you notice signs of unease.

Seriously, sweet basil might not be a thing in a few more years.

Downy mildew is not a big fan of extreme heat, which is good for us, but it is a huge fan of moisture, which is extremely not good for us. We cannot change the weather, but we can discourage excess moisture by watering basil plants at the soil line. That is to say, get drip irrigation or get on your knees and water only the soil surrounding the plant when your basil is looking thirsty. Do not get water on the plant leaves if you can help it at all. Basil doesn’t like wet feet, downy mildew or no. Also, water a little bit less than you’d like to, and make sure that you have some lovely soil that has fantastic drainage.

Speaking of soil, if you watched your basil plants go down hard last season, odds are there is still some downy mildew hanging out in your dirt, and you’d be wise to switch the soil out if you’re going to give basil another go. There are many strains of downy mildew that are attracted to many different vegetables, but fortunately each strain is only into the plant that it’s into. Thus, this year you can plant squash where you planted basil last year, and the squash will not succumb to that particular malady.

Spacing your basil out will also help immensely. Generally, I think the more veggies you can pack into a space the better; but with basil, in its present perilous state, it is not so. Give them room to breathe. This will create a less humid micro-climate for the algae, which travel by wind from plant to plant, so the farther they must travel to infect, the less likely they are to do so.

That is all you can do, and you should do all that you can, elsewise you may be kicking yourself a few years down the road, when sweet basil literally doesn’t exist anymore. You’ll wish you’d made that monster batch of your mama’s delicious homegrown pesto and stuck it in the freezer back in those halcyon summer months of ‘18.

IAN WILLSON| ian@southboundgardens.com


illustration MELISSA GUION