If you have ever planted potatoes and watched with joy as the tops appear through the soil, it can be quite disheartening to see those potato tops continue to grow and grow and then finally fall over onto the ground before they have had a chance to fully ripen.
Let’s look at why this happens and then find out what we can do to stop it from happening.
Why are my potato plants falling over?
There are two instances of why potato tops fall over. One is when the potato top has fully matured and is beginning to die back. This is known as senescence and is part of the ripening process. The potato tops will begin to change colour from bright green to dull green, then brown. The tops will shrink back towards the soil until they eventually end up lying flat on it. This is natural and happens at the end of the potatoes growing season.
The other instance is when the potato tops grow excessively large, causing it to fail under its own weight or will be blown over easily in a light breeze. This happens long before the potato plant has had a chance to fully ripen – as early as halfway through its growing season.
It is this second instance of excessive potato plant size that this article will address.
Usually when a potato plant falls over it is because the green tops have grown excessively larger than normal. Often there is one reason for this – too much fertilizer. To be specific too much Nitrogen.
Higher than required nitrogen causes the green leafy part of the potato plant to grow very large. This results in the top being more susceptible to being blown over, even in light winds. A normal potato plant can withstand blowing in a strong breeze, but a very large oversize potato top will topple over much easier.
While high nitrogen is the main reason for potato plants falling over there are a couple of further points to mention.
If your potato plants are grown in a very windy location there is a higher chance of them falling over – this is normally not an issue unless your location is renowned for being very windy.
Another reason for potato plants falling over is if they are planted singularly- for example, one potato plant in a bucket. If possible always grow your potatoes in plots along with other potato plants rather than on their own. Each plant will have another plant surrounding it which offers support for the stems and the group will withstand much stronger attacks from the elements.
What will happen to my potato plant if it topples over?
Usually when an oversized potato top falls over it will break a few or all of the main stems holding the leaves. The stems usually remain attached to the leaves and potatoes in the soil but they will be badly damaged and folded over. This results in the flow of nutrients between the leaves and potatoes being compromised- the plant will die back soon after and the potatoes in the soil will cease to grow any further.
How can I prevent my potato tops from falling over?
As I mentioned above, too much nitrogen fertilizer will cause your potato plant tops to grow too big. There are a couple of ways to address this.
- Take a soil sample at the time of planting and get it analysed for NPK. Compare your results to the fertilizer handbook to see how much of which nutrient your soil needs and add it.
- If you dont want to get involved with soil analysis, simply add a little P and K fertilizer to the soil. This will ensure the potato plant does not get any nitrogen and should grow normally.
- Avoid planting your potatoes in excessively windy areas.
- Try if possible to avoid planting single potato plants – try to plant your potatoes in a plot together, this will offer support and protection to all the plants
Now you are aware that excessive nitrogen fertilizer causes potato plants to fall over, you can plant your crop with the knowledge they will have a much better chance of standing until they are fully mature.