Silicon And Gardening: Do Plants Need Silicon In The Garden

Magnifying Glass Highlighting Si The Silicon Element On The Periodic Table
(Image credit: vchal)

If you garden, you know that there are certain essential nutrients necessary for plant health and growth. Most everyone knows of the big three: nitrogen, phosphorus, and potassium, but there are other nutrients, such as silicon in plants, that while not perhaps as necessary, play a vital role in growth and health. What is the function of silicon and do plants really need silicon?

What is Silicon?

Silicon makes up the second-highest concentration of the earth’s crust. It is commonly found in soil but can only be absorbed by plants in the form of monosilicic acid. Broadleaf plants (dicots) take up small amounts of silicon and accumulate very little into their systems. Grasses (monocots), however, accumulate up to 5-10% in their tissue, a higher than normal range over that for nitrogen and potassium.

Function of Silicon in Plants

Silicon seems to improve plant responses to stress. For instance, it improves drought resistance and delays wilting in some crops when irrigation is withheld. It also may boost a plant’s ability to resist toxicities from metals or micronutrients. It has also been linked to increased stem strength.

Additionally, silicon has been found to increase resistance to fungal pathogens in some plants, although more research needs to be conducted. 

Do Plants Need Silicon?

Silicon is not quantified as an essential element and most plants will grow just fine without it. That said, some plants have negative effects when silicon is withheld. For instance, research has shown that crops such as rice and wheat exhibit signs of lodging, weakened stems that easily collapse in wind or rain when silicon is withheld. Also, tomatoes have abnormal flower development, and cucumbers and strawberries have reduced fruit set combined with deformed fruit.

Conversely, a surfeit of silicon in some plants can result in flowering issues, and hence fruit deformities, as well.

While research shows some benefits of using silicon on agricultural crops, such as rice and sugarcane, silicon and gardening generally don’t go hand in hand. In other words, the home gardener does not need to use silicon, especially until further research has been established.

Amy Grant

Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.