Space weather has been known to cause disruptions to GPS and communications systems, and perhaps no one is feeling those headaches more than farmers this weekend. reports that the heightened solar activity over the last few days has led to outages in the GPS navigation systems that guide some modern tractors from John Deere and other brands. The technology has allowed farmers to plant more efficiently in ultra-tight, straight lines, but they’ve been advised to temporarily stop using it due to the potential for inaccuracies that could cause havoc down the line come harvesting time.

John Deere’s tractors connect to what are known as Real-Time Kinematic (RTK) systems, 404 reports, which allow for precision planting down to the centimeter level. If farmers were to go ahead and plant without their usual accuracy, “we expect that the rows won’t be where the AutoPath lines think they are” when it’s time to tend and harvest the crops, Landmark Implement, owner of some John Deere dealerships, told 404 Media.

The timing is terrible — it’s peak planting season for corn, and one Nebraska farmer, Kevin Kenney, told 404, “All the tractors are sitting at the ends of the field right now shut down because of the solar storm.” Many farms have had to pause planting, while others are carrying on and just hoping for the best.

The geomagnetic storm we’re currently experiencing is the strongest observed in the last 20 years, and reached G5 levels on Friday and Saturday morning, which is considered to be “extreme.” It later died down some to , but is expected to on Sunday evening when some intense but slower-moving coronal mass ejections (CMEs) from the sun reach Earth. That’s great , but not so much if your livelihood depends on the technology the storm is interfering with.