Is it Bad to Mow Over Dandelions? Does It Spread Them?

Dandelion is a super fast-growing herbaceous perennial that is notorious for invading lawns. They produce round, fluffy, white seed heads. The seeds have fine hairs attached that help them disperse their seeds over long distances via the wind. 

Mowing over dandelions once they have set seed is bad because it will spread them. Mowing over dandelions does not kill them. They regrow from their deep taproot. However, regular mowing before dandelions set seed will control their growth and prevent them from spreading in the lawn.

Dandelions flower in spring. They shoot up quite attractive yellow daisy flowers. However, to prevent the flowers from setting seeds and creating many more dandelions on the lawn, most people mow them at this stage. Regular, consistent lawn maintenance, along with painstakingly pulling each dandelion plant out by the root, is the only way to eliminate them long-term. 

Why Does Mowing Over Dandelions Spread Them?

Dandelions have evolved their round, fluffy seed heads to optimize their seed dispersal. The hairs attached to the seeds allow the wind to carry the seeds, spreading them over great distances. 

When you run a lawnmower over dandelions that have gone to seed, the seeds will disperse. Some will be flung by the action of the mower blades; others will stick to the underside of the lawnmower and fall when the mower is pushed around. 

Dandelion seeds germinate quickly when they are on or slightly below the soil. If there is not enough moisture or the temperature is too low for germination, the seeds will remain dormant in the soil.

Pull Dandelions Before Mowing 

Many people struggle with terrible dandelion infestations in their lawns, especially in the spring when the seeds germinate. Dandelions are difficult to control because they spread via their roots as well as their seeds. 

The only way to permanently kill dandelion plants is to pull them out by their roots. If a small piece of root remains in the ground, it will regrow. One needs to use a weeding tool to get the whole taproot out. 

If dandelions have seriously invaded the lawn, pulling out each and every plant is not realistically possible. However, by using a combined approach, pulling the weeds, and mowing the lawn to the correct height, one can control dandelion populations.

How To Avoid Spreading Dandelions 

Fortunately, there are ways to minimize the spread of dandelions on your lawn. 

• Mow dandelions before they set seed. If the flowers are mowed while they are still developing, there is zero risk of spreading any seeds.
• Bag the clippings if you need to mow the lawn with dandelions that have already formed seed heads.
• Set the lawnmower to the appropriate height. If the grass is cut too short, any dandelion seeds that fall onto bare soil will have enough light to germinate and grow. When grass is cut to the correct length, 
• Let the mulched clippings remain on the grass. The mulch will prevent dandelion or other weed seeds from germinating by blocking out sunlight. The mulches clippings are also high in nitrogen, so it will give the grass a boost.

Regular Lawn Maintenance to Control Dandelions

Most lawns go dormant in late summer and do not grow much over winter. One does not need to mow the lawn until early spring when the grass (and dandelions) starts to grow.

Early spring is the best time to begin mowing the lawn to control dandelions. When the flowers are still developing or have just opened, mow the grass with the lawnmower set to the highest length possible. 

Mow the lawn once a week during spring and summer until the lawn starts to go dormant again. Fertilizing the lawn with compost or slow-release organic fertilizer will benefit the grass and help it better outcompete the weeds.

Soil pH Affects Dandelions

Many plant species prefer growing in soil that has a certain pH. Dandelions like slightly acidic soil. By manipulating the soil conditions, one can suppress dandelion growth.

By applying dolomitic lime or baking soda to your lawn, you can make the soil more alkaline naturally. This will drastically slow the growth of dandelions on the lawn. 

Do Dandelions Harm Your Lawn?

Understandably, most people love the idea of a lush, green, weed-free lawn. They go to great lengths to maintain a dandelion-free lawn. Marketing of herbicides, weed-and-feed, and dandelion-killing chemicals has led to the widespread misconception that dandelions are bad for grass.

Dandelions are beneficial to the lawn and to the environment. In early spring, dandelions are an important source of pollen for bees early in the season, when there are few other flowers. Their deep tap roots break the soil apart, aerating it. This helps the grass grow better. 

Wrapping Up

Mowing over dandelions that have already produced their fluffy, white seed heads will spread them around the lawn and garden, even if you take precautions to prevent spreading the seeds. Cutting back dandelions’ foliage and flowers will not kill them. Dandelions regrow from their long taproot that grows deep into the soil. 

The only way to permanently kill dandelions is to pull each plant out by its entire taproot. If a small piece of root is left, it will regrow. Before mowing the lawn, pull out as many dandelions as possible, especially those that have set seed. By mowing the lawn, you will remove the flowers and slow the growth of the dandelion. 

Make sure you mow the lawn to the correct length, as this helps prevent dandelion seeds from germinating. If the grass is long enough to shade the soil surface, weeds will not grow. One can also suppress dandelion growth by applying dolomitic lime to the lawn. Dandelions prefer acidic soil, and making the soil more alkaline will slow their growth. 

When it feels as if you will never win the battle against dandelions in your lawn, remind yourself that they actually do not do any harm to the lawn. On the contrary, dandelions benefit the soil, the lawn, and pollinating insects like bees.