Final 2025 vegetable update - 9/10/2025

Natalie Hoidal and Marissa Schuh

Updates are over, we’re still here!

This will be our final update of the season. We know you still have a lot of farming to do this fall, but we generally find that there’s less to say in September as things start to wind down. It’s too late to make many management changes, and we start to shift our focus to winter programming. We’ll keep writing articles over the winter, we’re just shifting away from weekly crop by crop updates. Some other places you can find us this fall / winter / spring:

• Email us any time! (general vegetable hoida016@umn.edu, pest management mschuh@umn.edu)
• This fall, we have a few exciting field days where you can see examples of successful farmers at a variety of scales. At all of these field days, you’ll see farmers who still have a whole lot going on in late September, October, and even November. These include our Soil Health Bus Tours (sign up by this Friday for the first tour! And email Natalie if you’d like a free registration code!), and a succession planting and advanced high tunnel management at Farm Farm in Princeton.
• Keep your eyes out for a brand new 2 day vegetable farming intensive course! This will be for growers with a couple of years of experience who are hoping to hone their skills and production planning.
• Winter conferences - we’ll be at all of the common winter conferences including the Emerging Farmers Conference, the MN Organic Conference, the MN Fruit and Vegetable Growers Conference, the Sustainable Farming Association's annual conference, and Marbleseed. Come say hi if you’re attending any of these!

Prepare your beds now for an easier spring

Fall is a great time to invest in some bed prep for spring! As we’ve seen the last two years, spring in Minnesota can be extremely wet. Climate projections show that we’re likely to see more spring rain fall most years. This can seriously delay field work and throw our farm plans off before the season even begins.

By prepping some beds now and using cover crops in between, you can save yourself some labor in the spring and the cover crops can help to absorb early spring moisture while outcompeting weeds. Check out this video highlighting a research project where we tested this practice at Maple Ridge Farm in Aitkin, on the St. Paul campus, and in Waseca: https://youtu.be/IXrJrOKDmII?si=AhmN6cRQICfV7chu&t=197 

 

 Asparagus

We’ve heard plenty of reports of new asparagus spears popping up. Our best guess is that the pendulum swing of cool, wet, and warm weather has perennials a bit confused this fall. It’s likely a similar phenomenon to lilacs blooming in the fall. In general, we’re not too worried.

As soon as we get a hard frost, we expect the ferns to begin to die down (if they haven’t started to do so already). Wait until the ferns are completely brown, and then remove them. Fern removal can also wait until spring if needed, but fall fern removal helps to eliminate insect pests and foliar diseases that might otherwise overwinter on the ferns. Ferns can be chopped, mowed, or burned. If they are chopped or mowed, remove them from the field if possible and compost them off-site. If you struggle with asparagus beetle, fern removal or chopping ferns finely is critical in preventing beetles from spending the winter in your field.

Garlic

Garlic planting season is nearing. Now is a good time to start preparing beds for garlic planting to allow residues from your previous crop or cover crop to break down. It's also a great time to get a soil test (turnaround time is about 2 weeks right now) so that you have time to amend your soil.

Carrots and potatoes

We’re hearing reports of soft rots as farmers are digging up fall potatoes and carrots. This is especially common in areas of the state that saw torrential downpours this summer: Waseca, Litchfield, etc. These rots are impossible to miss a lot of the time - tubers and roots can be already half melted at harvest. However, these diseases can also develop and spread quickly in storage. They usually need a wound to enter the plant, but if they are on the surface, the process of sorting, washing, and storing fall crops can create wounds and bruises that let pathogens quickly spread postharvest.

Some general tips…

• Sanitize all harvest equipment and your storage facility regularly.
• Wait until crop is fully mature at harvest (most important for potatoes)
• Harvest carefully to avoid bruising and other harvest damage.
• Sort crops upon harvest. Remove all damaged stuff if you know that this pathogen is present.
• Dry crops as soon as possible, and do not wash them before storing them. Washing prior to storage can introduce excess moisture, and can also cause more bruising and abrasions.
• Maintain good ventilation in storage facility
• For potatoes, cure all tubers for 2-3 weeks at 50-55 degrees F with good air flow
• Monitor your storage areas and check regularly for wet spots and disease.

Melons & cucumbers

Melons and cucumbers had their last hurrah this week - any remaining melons in the field are likely the last ones of the season. Even though the weather is warming up again, most plants suffered from the cold weather and are unlikely to rally for a second round.

Tomatoes

Most tomato plants survived the cold snap and should have a couple more good weeks if they haven’t totally succumbed to disease. If you have indeterminate tomatoes in the field, this is the time to top them if you top your tomatoes (cut the tops off so the plants focus their energy on ripening existing fruit). This is also the time of the year when it’s worth taking some good notes about which varieties are still hanging on. In high tunnels, we tend to see big differences by September between plants with leaf mold + gray mold resistance, and those without. In fields, the main differences are between plants with resistance to the common foliar pathogens like early blight, septoria, and fusarium.

We’re also seeing more tomato viruses this year. If you think you’re seeing virus symptoms, please reach out! Identifying which virus is causing problems can inform your management. Some require extensive clean up and sanitizing, and others don’t, as they are less likely to overwinter. In high tunnels, figuring out exactly which virus you’re seeing can also help you identify the vector - whether it’s spread by aphids, thrips, whiteflies, leafhoppers, or something else - which can inform your management next year.

Brassicas

Brassicas like it cool, but last week was a little much, even for them. Broccoli, cauliflower, and even kale slowed down quite a bit during the cold snap, and farmers are seeing delayed crops. Temperatures are warming up again, but nights should stay pretty comfortably below 70 degrees, which is ideal for head forming Brassicas. We expect these crops will catch up and be pretty happy over the next couple of weeks. So far this summer, cauliflower has been small and a little funky due to heat and moisture issues, but conditions look pretty good for some nice fall cauliflower crops. The next 10 days or so look fairly dry, which should help to prevent the spread of Alternaria and Black rot, our notorious fall Brassica diseases.

Let us know if these updates are helpful!

Just as crops wind down this time of year, so do our updates. Filling out the below survey helps us figure out if these crop updates hit the mark over the growing season. We appreciate any feedback you share!