Garlic Troubleshooting Guide

Garlic is pretty tough.

That doesn’t mean that you aren’t going to run into some problems. Garlic is prone to several different diseases and pests. Most of these problems come directly from the soil so it is important that you rotate your crop every year.

Here are some of the most common problems you may run into with your garlic crop and what you might do about them.

Overwatering can cause rot. If you notice your plant yellowing or dying back, check a few of them and check the water content of the soil. If you see that rot is beginning to form, cut back on the watering.

Bulb mites will often grow under the roots of the bulb and can result in stunted garlic plants. They are white, shiny and fat. They can be very tough so they best way to deal with them is by rotating your garlic plantings.

The pea leafminer won’t cause you too many problems. They show up initially as tiny eggs laid within the leaf tissue. When they hatch, the larvae tunnel inside the leaves. When they mature, they leave the plant as tiny black and yellow flies. The tunneling done by the larvae is really no big deal to your garlic plant but you still want to be careful because these guys can pose a serious threat to other leafy plants nearby.

The wheat curl mite is another one that, while making your plant look pretty rough, doesn’t pose a serious threat. You’ll know you have it if the garlic leaves are streaked and twisted and overall growth stunted. The wheat curl mite can cause problems at harvest. Your cloves will dry out and crumble if its in there. This is another one that can be dealt with through a hot water treatment just before planting.

Basal Rot is a slow developing fungus, typical of warmer climates, that often causes the leaves of the plant to die back. Often times, symptoms of the rot are not even evident until post-harvest when you may note a white fungus at the bottom of the bulb. Keep an eye out for this once your garlic is hanging in storage.

White Rot, more typical of cooler climes, looks a lot like basal rot but white rot often tends to simply kill the garlic plant outright. This is a tricky one because while you can reduce the chance of white rot by dipping your seed clove in hot water right before planting, too high a temperature can kill your seed clove.

Downy Mildew looks like a whitish, furry growth on the leaves. They may also yellow. Young plants may die while older ones will see stunted growth. If you suspect downy mildew, check the garlic you’ve stored. It will be shriveled, have a blackened neck and might feel moist to the touch. Downy mildew can survive for years in the soil. It loves to be wet and is often transported by moving water so go for wide-spacing of your rows, good air circulation and avoid over watering.

Botrytis Rot, also known as “neckrot” will hit the stems with a gray fuzz. The stems will also fill with water. Typically, “neckrot” will hit your bulbs and/or plants in warm, wet weather so be sure to get your bulbs rapidly dried out before storage and make sure they get a lot of air circulation. Cooler storage temperatures may also help. In the garden, be sure to use disease free bulbs and again, space your rows and get lots of air between the plants.

Penicillium Decay looks like blue-green mass on your cloves. It will dramatically reduce the growth of your plants. Be sure your bulbs are properly dried before storage. When planting, take care to put the clove in immediately after it is ‘cracked’.

Nematodes show up in a multitude of ways. Common symptoms include erratic plant stand in the field, stunted plants, yellowing, deformed bulbs, and stem swelling. You’ll actually have to get your field tested by a lab if you want to find out about these little buggers. If you have them, you’ll want to rotate your plants away from them…if possible. They can move around quite a bit. A traditional way of dealing with them is giving the cloves a hot water soak right before planting.

You may find that you have other issues. Some genetic abnormalities can resemble disease symptoms. You might see a great variety of colors in the leaf of your plant. This is actually quite common and results in reduced photosynthesis or bulb deformation. Another common genetic problem may result in a breakdown of the outer cloves of garlic where sunken tissue will turn a dark yellow color.

Finally, the clove turns very soft, clear and sticky. There is not much you can do about this except to remove the problem cloves from your collection. Don’t plant them again!

{ 8 comments… read them below or add one }

Penny May 17, 2010 at 7:10 am

would like to know how to grow a garlic bulb that has been standing in bit of water, getting roots and three green leaves sprouting from the top?

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Separate the bulb into cloves and plant pointed side up. Let me warn you, that sometimes it doesn’t work to plant garlic from the grocery store because of your climate. Check to see what varieties of garlic will grow in your area. With that said, plant it and see if it works!

mary halchuk May 27, 2010 at 4:15 pm

I planted my garlic cloves in October. The plants are well over 2 ft. tall. They looked very healthy until about 2 weeks ago. A yellowing began at the base s of the plants which is now traveling half up the plant. Today I noticed a red bumpy ‘rash’ on the leaves, and the areas around this rash are turning yellow. Will not make it to harvest at this rate. Can you tell me how I could possibly save the plants. I purchased the bulbs at an organic farm on Westham Island, Ladner, B.C. Cda.
Advise would be very much appreciated. Thank you.

Joanne August 21, 2010 at 2:29 pm

Wish I’d seen this earlier because what you’re describing is normal. Once the bottom leaves are yellowing, it’s time to harvest. Did you have scapes?

F.BECKER October 23, 2011 at 3:56 am

WILL I GET BIGGER BULBS IF I CUT THE HEADS OFF, OR SHOULD I LET THE HEADS GO TO SEED ???

Chris Z June 12, 2013 at 9:45 am

My garlic has all fallen over. What causes this?

John June 24, 2013 at 8:39 pm

We planted our garlic last fall on October 20 (very wet conditions).
Aprox. half the garlic grew well, the rest seemed quite reluctant to grow and now June 24 is only about 2 inches tall.
Don’t see any insect problems, what could our problems be ?
John

Abigail R Sorensen October 23, 2016 at 10:12 am

I’m new to garlic planting and followed the farmer’s almanac planting recommendation for my area, planting in the beginning of October (I live in Chicago). We have had unseasonably warm weather and now I have about 6″ sprouts, it’s October 23 today. The 10 day forcast has the low at 42. What should I do?

Thank you,
Abigail

John August 29, 2017 at 6:07 pm

I see people (and garden catalogs) say plant in fall and harvest in spring, or plant in spring and harvest in fall. I planted my garlic about three years ago and it gives nice purple flowers, none of them seem to be producing bulbs. Did I not get garlic, even though the big box store had it labeled as such?

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