What's The Function Of Nitrogen (N) In Plants? | Greenway Biotech

How to Fix Nitrogen Deficiency in Plants

Correcting nitrogen deficiency involves both immediate treatment and longer-term soil building strategies. The approach you choose often depends on how severe the deficiency is and whether you prefer organic or conventional methods.

Fast-Acting (Water-Soluble) Nitrogen Sources

When plants are visibly deficient and need correction within days, water-soluble nitrogen fertilizers are generally the most effective option. These dissolve completely in water and deliver nitrogen directly to the root zone:

Ammonium Sulfate 21-0-0 — Provides both nitrogen (21%) and sulfur (24%). Works well in alkaline soils and helps lower soil pH gradually.

Mix: 12 grams (approximately 1 tablespoon) per gallon of water

Apply: 1 cup (8 fl oz) of solution per plant for containers; 1 gallon per 50 sq ft for beds

Dose received: Approximately 0.16 g actual nitrogen per cup of solution (12 g ÷ 16 cups × 21% N)

Coverage: One gallon of mixed solution treats about 16 container plants, delivering ~2.5 g total nitrogen

Calcium Nitrate 15.5-0-0 — Delivers nitrogen in nitrate form (immediately available) plus 19% calcium. Often preferred for fruiting crops where calcium prevents blossom end rot.

Urea 46-0-0 — The most concentrated nitrogen fertilizer available. Best for large-area applications and situations where maximum nitrogen per dollar matters. Because urea contains 46% nitrogen, you need roughly half as much product compared to ammonium sulfate (21% N) to deliver the same nitrogen rate — making it the most economical option for broadcast applications.

How to Add Nitrogen to Soil Naturally

For longer-term soil building, organic nitrogen sources release nutrients gradually as soil microorganisms break them down:

Blood Meal 13-0-0 — One of the highest-nitrogen organic fertilizers available. Releases over 4–6 weeks and provides a noticeable greening effect within 1–2 weeks.

Feather Meal 12-0-0 — Slower release than blood meal, providing steady nitrogen over 2–3 months. Works well as a pre-plant amendment.

Crustacean Meal 4-0-0 — Lower nitrogen but adds chitin to soil, which can stimulate beneficial microbial activity and may support natural pest resistance.

💡 Pro Tip: Combine Fast and Slow Sources

For severe deficiencies, many experienced growers apply a water-soluble nitrogen fertilizer for immediate correction while simultaneously working an organic meal into the soil for sustained feeding. This "quick fix plus long-term" approach often delivers the best results.

Related: Top Water-Soluble Fertilizers for Thriving Gardens