As spring approaches, many homeowners and landscapers apply fertilizer to lawns and gardens to encourage healthy growth. However, spring snowstorms sometimes hit after those early fertilizer treatments. So an important question arises: will snow hurt fertilizer effectiveness?
As a professional organic fertilizer production manufacturer, I took a deep dive into the latest agronomic research on this topic. Here’s what I learned about how snow impacts common fertilizers used on lawns, trees, shrubs, and gardens.
How Fertilizers Work
Before jumping into the snow issue, let’s do a quick fertilizer refresher.
Fertilizers contain key nutrients that plants need to grow and thrive. The three primary macronutrients are:
- Nitrogen – Stimulates leaf and stem growth
- Phosphorus – Aids root, flower, and fruit production
- Potassium – Supports overall plant health
Fertilizer bags have three numbers, representing the percentage of these nutrients they contain. A 10-10-10 fertilizer has equal ratios, while a 16-4-8 has more nitrogen.
When fertilizer gets watered into the soil, the nutrients break down through chemical processes. This releases them for plant roots to absorb. From there, they travel up the stems and leaves, supporting growth and production.
Key Takeaway: Fertilizer needs moisture to break down and release nutrients. Frozen, snow-covered soil lacks that moisture.
How Snow Affects The Fertilizer
Impact on Lawns
Lawn fertilizers are predominantly nitrogen-based. A spring snow typically won’t affect nitrogen that was applied the previous fall. However, early spring nitrogen treatments right before a storm may suffer some loss.
Research from Michigan State University tested losses from urea (a nitrogen fertilizer) applied to grass before snow events. They found minor nitrogen losses – 10-15% at most.
Another study in North Dakota analyzed losses when the fertilizer stays on the snow surface during the melt. Approximately 20% washed away rather than soaking into the soil. In contrast, when they applied fertilizer one day after melt finished, effectiveness was the same as fall application.
The verdict? Spring lawn fertilizing between snowstorms carries moderately higher risk than fall application. However, as long as some does penetrate the soil, lawns will still see benefits. Postponing reapplication until after the last snowmelt is the safest option.
Effect on Gardens
Gardens often receive more phosphorus and potassium versus lawns. And these nutrients aren’t as mobile, so spring snow has little impact on them.
As for nitrogen, vegetable garden fertilizing also typically occurs later, after the last frost. By that point, spring snowstorms have usually finished.
However, early crops like peas and spinach get planted sooner. If snow covers newly planted rows treated with nitrogen fertilizers, minor nutrient losses could occur. But research from the University of Illinois found spring snowmelt and rains compensate for it.
Bottom line – The effect of spring snow on garden fertilizer is negligible overall. Once any surface meltwater drains away, the remaining nutrients get incorporated into the soil effectively.
What About Trees and Shrubs?
Trees and shrubs often receive treatment too, whether via late fall or early spring feeding. Snow accumulation generally poses little concern in these cases.
According to Purdue University studies, only severe, extended snow cover that lingers into late spring may impact nutrient availability. Under these conditions, some leaching can occur from the fertilizer lingering at the frozen surface.
However, snow’s insulating properties are beneficial on balance. Snow cover moderates soil temperatures, reducing extremes that could damage roots. It also provides ample moisture as it gradually melts.
Key Finding: Research shows limited spring snow troubles for tree and shrub fertilizers. The insulating snow blanket offers more positives than negatives regarding nutrient retention.
Will Snow Hurt Fertilizer?
In summary, spring snowstorms may cause minor fertilizer nitrogen losses on lawns if the treatment occurred shortly before accumulating snows. However, the risks are relatively small, and reapplication after the last melt can resolve any deficiencies.
Meanwhile, garden fertilizers experience little trouble from spring snow thanks to later application timing. And trees/shrubs receive insulation benefits outweighing any spring nutrient issues.
So while heavy late-season snowfall may make lawn care tricky, it causes few real problems for fertilizer effectiveness overall. A bit of patience for full melt to occur, then reapply any areas showing deficiency. Within a few weeks, all your plants will be thriving as usual!
