Answer: No, it cannot.
Lawn feed or fertilizer cannot be used on plants. For many people, fertilizer is fertilizer. It serves one purpose and it should, therefore, work when applied on any plant. Well, some fertilizers can be used on a wide variety of plants and trees. However, the majority of fertilizers are specific to certain plants and, therefore, it makes no sense to use them on some other plants. A good example is lawn feed/ fertilizer. It is perfect for use on most types of grass but it cannot be used on plants such as vegetables and the likes.
Why You Should Never Use Lawn Fertilizer on Plants
You now know that some fertilizers are not compatible with some plants because they are designed or created with certain specific plants in mind. Now it is time to know why exactly you should never use lawn fertilizer/ feed on garden plants.
The reason why is that lawn fertilizer has a significantly different nutrient profile (composition and ratio of potassium, phosphorus, and nitrogen) when compared to garden fertilizer. So when used, it usually does very little other than to add chemicals to the ground which can be washed off to water bodies resulting in pollution and ecological damage.
Moreover, lawn fertilizers are nowadays made with pesticides or herbicides in them. Therefore, spraying them on garden plants or vegetables can result in you consuming toxic chemicals or in the killing of certain plants and insects responsible for pollination.
So there are, in fact, two reasons why you should never use lawn feed on plants. First, lawn fertilizer is not meant for plants and, therefore, spraying it on plants is useless. Second, lawn fertilizer has chemicals that can destroy plants and pollinators.
The Differences between Lawn Feed and Garden Fertilizer
Plants need several nutrients to thrive. Most fertilizers supply three main nutrients – potassium, phosphorus, and nitrogen. The bags, packages, and containers in which fertilizers are packed usually have a ratio indicating the proportion of these three main nutrients corresponding to N.P.K (nitrogen. phosphorus. potassium). For example, if you see the ratio 20-15-10 on a fertilizer package. It automatically means that 20 percent of the fertilizer is nitrogen, 15 percent is phosphorus, and 10 percent is potassium. The remaining part of the fertilizer is made up of other nutrients/ ingredients.
Lawn fertilizers have very different N.P.K ratios when compared to garden fertilizers. They usually have very high levels of nitrogen compared to garden fertilizers. Their levels of nitrogen are high to promote and maintain green growth. This makes them perfect for lawns. At the same time, it makes them very unsuitable for vegetables, fruit trees, and flowers. This is because too much nitrogen stunts the growth of vegetables, fruits, and flowers. So because of the high percentage of nitrogen in lawn fertilizers, if you apply them on fruits and vegetables, their leaves may thrive, but they will most likely fail to produce fewer fruits and vegetables.
Lawn fertilizers usually have a lot of nitrogen and little or no phosphorus and potassium. This is despite the fact that plants need phosphorus for photosynthesis plus root growth, and that the nutrient improves plant disease resistance. Plants need potassium for the transport of water and nutrients and for maintaining strong stems and roots. It makes sense that lawn fertilizers usually have little or no phosphorus and potassium because they are designed for grass. Grass is a very simple plant form compared to vegetables, fruit trees, and garden plants. It does not have many needs.
In contrast, garden fertilizers usually have relatively higher percentages of phosphorus and potassium because they are designed to support complex plants in the name of fruit plants, vegetable plants, and flowers.
Examples of Lawn Fertilizer N.P.K ratios
One of the best lawn fertilizers is the Sta-Green Lawn Fertilizer. Its N.P.K ratio is 29-0-5. This means every 100 pounds of this fertilizer has nitrogen (29 pounds), phosphorus (0), and potassium (5 pounds). It can definitely help grow grass but it would not be appropriate for garden plants.
Another good lawn fertilizer is the Milorganite Slow-Release Nitrogen Fertilizer. Its N.P.K ratio is 6-4-0. This means every 100 pounds of this fertilizer has nitrogen (6 pounds), phosphorus (4 pounds), and potassium (0).
The Scotts Turf Builder Starter Food is also a great lawn fertilizer. Its N.P.K ratio is 24-25-4. This means every 100 pounds of this fertilizer has nitrogen (24 pounds), phosphorus (25 pounds), and potassium (4).
Examples of Garden Fertilizer N.P.K ratios
One of the best garden fertilizers currently available on the market is the Scott’s All-Purpose Flower & Vegetable. Its N.P.K ratio is 10-10-1o. This means every 100 pounds of this fertilizer has nitrogen (10 pounds), phosphorus (10), and potassium (10 pounds). It is, therefore, very balanced and great for growing vegetables, fruits, and flowers in gardens.
The J R Peters 52024 Jacks Classic No.1.5 All-Purpose Fertilizer is also a good example of a very balanced fertilizer. Its N.P.K is 20-20-20. This means it has equal significant percentages of the big three nutrients. It is perfect for growing different types of vegetables, fruits, and flowers. It is, in fact, an Amazon’s Choice because of how many people find it useful and productive.
Why Even Balanced Lawn Fertilizers are Not Good
As mentioned earlier, there are two reasons why lawn fertilizers should not be used on garden plants. The first one is obviously because they do not have the right nutrients. And the second one is that they have herbicides/ pesticides.
The second reason is probably the most important reason why you should never use a lawn feed or fertilizer on a garden plant. Many lawn fertilizers, especially of the weed ‘n feed type, are a combination of fertilizer and herbicide. They are meant to simultaneously feed lawns and kill weeds in amongst the grass.
Because they have an herbicide, they can kill some garden plants. They can also kill insects such as bees that are needed for pollination. So using lawn fertilizers on garden plants can be quite disastrous.
What to Know Before Using a Garden Fertilizer
Garden fertilizers are the only fertilizers that can be used on garden plants. However, not every garden fertilizer is perfect for every garden. To know which garden fertilizer is perfect for your garden, you should test your garden soil. This will tell you the nutrient profile of your soil and what is needed. It will help you to know which of the big three nutrients you need to add, and, therefore, assist you in choosing a garden fertilizer with the right N.P.K ratio.
You also need to know that it is best to fertilize garden plants when the soil is moist. Because moist soil help nutrients to reach the roots. Dry soil on the other hand will result in dry nutrients accumulating in the soil. So only fertilize when the soil is moist.