The harvest season for direct-sown onions in Poland usually falls in August and September, and the exact timing is decided by the field, not the calendar. We grow onions across roughly 150 hectares in the Żuławy region, and every year we plan the harvest to bring the crop in at the best possible moment, neither too early nor too late. In this post we show when our season begins, how we know the onions are ready, and what the whole journey from the field to storage looks like.
When the onion harvest season begins
Our direct-sown onions ripen from late summer. In Żuławy conditions that usually means the second half of August and September, because the cooler, maritime climate stretches the growing season compared with the south of the country. Onions grown from sets come off the field earlier, often at the turn of July and August, but we base our crop on spring sowing, so our harvest falls later.
You can't lock the timing into the calendar. Every season is different, because ripening depends on the weather across the whole summer. That's why we watch the plant, not the date. As the end of the growing season approaches, we check the fields every day and wait for the right moment, along with a dry, sunny day to go in.
How we know the onion is ready
The most important signal is the bent-over tops. When the leaves on most plants lose their firmness and fall to the ground, the onion stops building yield and starts to ripen. That's a sign the outer skin is maturing, the neck is drying down, and the onion is ready to be lifted.
We also look at the onion itself: the colour of the skin, whether the neck is closing, and the overall state of the field. On top of that comes the weather. We harvest onions on dry, sunny days, because then less soil sticks to the crop and the risk of storage diseases is lower. Harvesting in the wet is a straight road to rot in storage.
The onion keeps the soil profile open all season long, right up to harvest. That suits weeds, so the end of the season is also about keeping the field clean for us, so we bring in just the crop and not the crop mixed with weeds.
Our work calendar during the harvest season
The harvest isn't a single day, it's several weeks of well-ordered work. Across roughly 150 hectares we won't bring everything in at once, so we plan the order of the fields and the pace so the chain from lifting to storage has no downtime. Below is a short picture of what we do and when.
| Stage | When (roughly) | What we do |
|---|---|---|
| Ripening | August | We watch the fields and wait for the tops to bend over |
| Getting ready for harvest | turn of August and September | Topping the leaves, lifting the onion with the Grimme rig |
| Main harvest | September | Self-propelled combine, harvesting two rows at once |
| Hauling from the field | as we go | John Deere 6930 Premium with a Wielton tridem trailer, anti-bruise covers |
| After harvest | September and on | Cleaning, drying for 2 to 4 days, sorting, storage |
The pace can be high. Our self-propelled combine can harvest up to 150 tonnes per hour, taking two rows at once. We describe all the equipment we use for this in our machinery park, and we break down the machine harvest itself in the post about the onion combine.
Harvest without damage, because quality starts here
The onion comes off the field in the same state it reaches storage in. Every bruise is a potential spot where rot will later start. That's why we set up the whole harvest gently: emptying the combine tank on the move, filling the trailer from the front, and anti-bruise covers that protect the crop in transport. It's a simple rule, but it decides how much onion makes it to sale in good shape.
The onion comes off the field dirty and damp, so right after harvest it goes for cleaning and drying. In our maritime climate we usually dry it for 2 to 4 days, closing the neck at the leaf base and removing excess moisture before it goes into store. Only then does the onion go to storage, where we keep watch over temperature and humidity, which we cover in more detail in the post about storing onions.
The weather runs the season
The harvest season plays out to the weather's tune, and the weather can stir things up properly. 2025 was very wet for us: in July we had up to 150 to 220 litres of water per square metre in a single day, with flooding and drainage canals bursting their banks. The wet soil compacted, the yield filled out less, and the pressure from secondary weeds was high. Seasons like that show that a good harvest starts long before the combine goes in, in an even field and a healthy plant.
That's why we keep our finger on the pulse to the end of the season. We react to forecasts, shift the order of the fields, and plan our runs around weather windows. We show the whole growing year, from sowing to this moment, in the guide on growing onions in Żuławy.
From the field straight to the customer
A well-ordered harvest season isn't art for art's sake, it's the basis of a reliable supply. Thanks to our own storage for around 1300 tonnes, we don't have to sell everything straight after harvest. We control sales over time, and we ship the onion fractioned and sorted, in a form matched to the customer. We describe how we work in wholesale in the post about vegetables from Żuławy in wholesale, and you'll find the details on varieties and supply formats in our onion offer.
Frequently asked questions
When are onions harvested in Poland?
Direct-sown onions are most often harvested in August and September, and onions from sets a bit earlier, at the turn of July and August. For us, in Żuławy, the harvest usually falls in the second half of August and in September, because the maritime climate stretches the growing season.
How can you tell an onion is ready to harvest?
The surest sign is the bent-over tops, that is, leaves losing their firmness and falling to the ground. On top of that comes a coloured, dry skin and a closing neck. We read the timing from the field, not the calendar.
Are onions harvested in the rain?
No. We harvest onions on dry, sunny days. Harvesting in the wet means more soil on the crop and a greater risk of rot in storage, so we wait for the right weather window.
How long does the onion harvest season last?
For us it's several weeks, because across roughly 150 hectares we bring the crop in field by field, not all at once. After harvest there's still drying for 2 to 4 days and sorting.
What happens to the onion right after harvest?
From the field the onion goes for cleaning and drying for 2 to 4 days, then for sorting and into store. There we keep watch over temperature and humidity so the crop makes it to sale in good shape.
What do you harvest onions with?
First we top the leaves and lift the onion with the Grimme rig, and the main harvest is done by a self-propelled combine taking two rows at once, with a capacity of up to 150 tonnes per hour. Hauling is handled by a John Deere 6930 Premium with a Wielton tridem trailer.
Looking for onions from a proven Żuławy harvest? Get in touch through our contact page or take a look at our onion offer. See also how we grow onions in Żuławy throughout the season.
