Onion Leaves Tell Their Own Story

We were out counting the leaves on our onion plants this evening. No, we weren't bored and had nothing better to do. We are approaching the summer solstice when we have the longest days of the year here in Minnesota. This is the time when long day onions start their bulb enlargement. The number and size of the leaves on your onions will indicate the size of the onions bulb. 

This is because each leaf produces one ring on the onion. So the more leaves the onion has the more rings it will have and the larger the leaves, the larger the rings. Woohoo, now we are all going to be out counting our onion leaves, as well you should be.

Typically an onion produces a pair of leaves every two weeks during the growing season after it gets established after transplanting, The onion should be fertilized organically every 2-3 weeks. The largest leaf is generally the ninth leaf and this is the time that you want to do your last fertilization as the onions peak nitrogen needs are then. Also the plant is making the transition from is green leafy stage to being a super storage machine.

The perfect number of leaves is a lucky 13 and if the onion produces this many leaves it is usually a sign that the plant is approaching maturity. Not all onions will produce 13 leaves, sometimes 9 to 12 leaves are produced, depending on the conditions. Not to worry if you don't get 13, you can still have some beautiful onions that will keep well and be delicious to eat.

For jumbo onions that break the records at the fair, strive for the lucky 13.

So what number did we get on our onions?  We found some twelves and a few tens, the onion pictured above has eleven leaves (the first is hidden by the second). So things are looking good.

They haven't started to enlarge yet. In a normal year we would have seen some bulb enlargement by now, I think this is because we had to plant them about three weeks late. They are just getting to the mature stage now and enlargement will follow. We would often be harvesting baseball sized onions by now and be well on the way to the slow pitch size. We might not get those huge sizes this year, but I could be wrong as the season has been very good in all other respects. We have weeded well and fertilized with fish several times. Water has been abundant.