Lettuce Fertilizer 8-15-36 | Chelated Micronutrients | Hydroponics, Soil & Foliar Application
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- $ 24.99
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- $ 24.99
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Lettuce Fertilizer 8-15-36
Unlock the full potential of your leafy greens with our premium water-soluble 8-15-36 formula. High potassium delivers crisp texture and extended shelf life while chelated micronutrients ensure nutrient-dense harvests for soil, hydroponic, and foliar growing.
Ideal Applications
FEATURES
⚖️ Optimized 8-15-36 Ratio
Engineered specifically for leafy green crops. Moderate nitrogen (8%) promotes healthy leaf development without excessive, leggy growth while very high potassium (36%) ensures crisp texture and extended shelf life.
🥬 Crisp Texture & Long Shelf Life
High potassium strengthens cell walls for that perfect crunch consumers expect, while improving post-harvest quality so your greens stay fresh days longer.
🚫 Tested for Heavy Metals
Every batch is independently lab tested for heavy metal content so you can grow food for your family or customers with confidence in what you're feeding your plants — and yourself.
🌊 100% Water Soluble
Dissolves instantly in cold water with zero residue. Safe for drip lines, aeroponics (clog-free), NFT channels, and fine mist foliar sprayers.
🛡️ Tip Burn Prevention Support
Balanced nutrition with moderate nitrogen reduces rapid growth that outpaces calcium transport — the primary cause of lettuce tip burn. Pair with Cal-Mag Plus for complete protection.
🌿 Deep Green Color
Chelated iron (0.10%) and manganese ensure rich chlorophyll production for the deep green color that consumers associate with freshness and nutritional value.
💧 Soil, Hydroponic & Foliar Versatility
Equally effective in garden soil, raised beds, containers, all hydroponic systems (NFT, DWC, ebb and flow, drip, aeroponics), and as a foliar spray. Scales from home gardens to commercial operations.
🔬 Complete Micronutrient Package
All six essential micronutrients in precise ratios — iron, manganese, zinc, and copper are EDTA-chelated to prevent lockout in high-pH water, while boron and molybdenum are supplied in highly available mineral forms.
🌱 Microgreen & Baby Leaf Ready
Easily scaled to quarter or half strength for microgreen and baby leaf production. Single applications at low EC deliver complete nutrition for fast-turnover crops.
📋 CDFA Registered & Lab Verified
Registered with the California Department of Food and Agriculture. Third-party lab tested for guaranteed analysis, purity, and compliance with state fertilizer standards.
DERIVED FROM
Our 8-15-36 formula is blended from premium-grade, solution-grade raw materials — each chosen for purity, solubility, and plant availability.
Macronutrient Sources
Monopotassium Phosphate (MKP) 0-52-34
Primary phosphorus and potassium source. Fully water-soluble with low salt index.
Potassium Sulfate 0-0-53
Additional potassium plus sulfur for enzyme activation and protein synthesis.
Ammonium Sulfate 21-0-0
Ammoniacal nitrogen source that helps lower root-zone pH for better nutrient uptake.
Micronutrient Sources
Chelated Iron EDTA
EDTA-protected iron for chlorophyll synthesis. Stays available even in alkaline conditions.
Chelated Manganese EDTA
EDTA-chelated for photosynthesis enzyme activation and disease resistance.
Chelated Zinc EDTA
EDTA-chelated zinc for auxin production, growth hormones, and leaf development.
Chelated Copper EDTA
EDTA-chelated copper for lignin synthesis, enzyme activation, and plant structural integrity.
Boric Acid
Highly available boron source for cell wall strength and calcium uptake. Not chelated — supplied in mineral form.
Sodium Molybdate
Trace molybdenum source for nitrogen metabolism and enzyme function. Not chelated — supplied in mineral form.
SCIENCE BEHIND THE FORMULA
8-15-36: Engineered for Leafy Green Performance
Understanding why our 8-15-36 formula works so well for lettuce and leafy greens requires looking at the unique nutritional demands of these crops, where leaf quality, texture, and shelf life are the primary goals.
🌿 Nitrogen — 8% (Controlled Leaf Growth)
Leafy greens need sufficient nitrogen for chlorophyll production and leaf development, but too much creates overly succulent tissues prone to disease, reduced shelf life, bitter flavors, and increased nitrate accumulation. Our 8% strikes the ideal balance for healthy, flavorful greens.
🌸 Phosphorus — 15% (Roots & Energy)
Phosphorus develops strong, efficient root systems for maximum nutrient uptake, enables rapid ATP production for cellular energy, supports photosynthesis and sugar transport, and promotes early establishment for faster maturity.
⭐ Potassium — 36% (Texture & Quality)
Leafy greens are heavy potassium feeders. Potassium regulates stomatal function and water use efficiency, activates over 60 enzyme systems, strengthens cell walls for crisp texture, enhances disease resistance, and extends post-harvest shelf life significantly.
Essential Micronutrients
🧲 Iron (Fe) 0.10%
Chelated EDTA. Essential for chlorophyll synthesis and photosynthesis. Prevents interveinal chlorosis (yellowing between leaf veins) that reduces market value in leafy greens.
⚙️ Manganese (Mn) 0.05%
Chelated EDTA. Activates enzymes for photosynthesis and chlorophyll formation. Critical for disease resistance and maintaining deep green color.
🌱 Zinc (Zn) 0.05%
Chelated EDTA. Required for auxin production and protein synthesis. Deficiency causes stunted growth and reduces leaf size — critical issues for leafy green production.
🔗 Copper (Cu) 0.05%
Chelated EDTA. Involved in lignin synthesis for strong cell walls and disease resistance. Important for enzyme function and structural integrity.
🧱 Boron (B) 0.02%
Boric Acid (mineral form — not chelated). Critical for cell wall formation and calcium utilization. Deficiency causes tip burn in lettuce and poor leaf development.
🔬 Molybdenum (Mo) 0.0005%
Sodium Molybdate (mineral form — not chelated). Essential for nitrate reduction and nitrogen metabolism. Deficiency causes yellowing and poor growth in leafy vegetables.
Why High Potassium for Leafy Greens?
🥬 Crisp Texture
Strengthens cell walls for that perfect crunch consumers expect in quality lettuce and greens.
🛡️ Disease Resistance
Reduces susceptibility to tip burn, downy mildew, and bacterial leaf spot common in leafy crops.
🍃 Enhanced Flavor
Improves sugar content and reduces bitterness for better taste profiles in salad greens.
📦 Extended Shelf Life
Maintains freshness days longer after harvest, reducing waste and improving marketability.
💧 Water Efficiency
Improves stomatal control and drought tolerance for consistent growth even under grow lights.
🌡️ Stress Tolerance
Helps plants cope with temperature fluctuations, heat stress, and environmental variability.
APPLICATION RATES & DIRECTIONS
Below are recommended rates for lettuce, kale, spinach, and all leafy green crops.
Soil Application
| Application Method | Rate | Frequency | Notes |
|---|---|---|---|
| Per Plant | 3g (½ tsp) | Every 4-6 weeks | Apply around base |
| Broadcast (per 100 sq ft) | 100-200g | Every 4-6 weeks | Water in thoroughly |
| Row Application | 2-4 lbs/100 ft row | At planting & mid-season | Side dress 2" from plants |
| Per Acre | 660-1500 lbs | Every 4-6 weeks | Based on plant density |
Foliar Application
| Concentration | Application Rate | Frequency | Best Time |
|---|---|---|---|
| 0.5-1% Solution | 5-10g/liter water | Every 1-2 weeks | Early morning/evening |
| Per Plant | 1g in 100ml water | Weekly | Avoid hot sun |
| Per Acre | 200-500 lbs in 100 gal | Every 1-2 weeks | Cool, calm conditions |
Hydroponic Application (per 100 gallons)
| Growth Stage | 8-15-36 Amount | Cal-Mag Plus | pH Range | EC/PPM |
|---|---|---|---|---|
| Seedling/Transplant | 0.25 lbs | 250-500 ml | 6.5-6.8 | 0.8-1.0 EC (560-700 PPM) |
| Vegetative Growth | 0.5 lbs | 500-1000 ml | 6.4-6.7 | 1.5-1.8 EC (1050-1260 PPM) |
| Mature/Harvest | 0.5 lbs | 1000 ml | 6.0-6.5 | 1.8-2.2 EC (1260-1540 PPM) |
Optimal Feeding Through Growth Stages
Seedling (Week 0-2): Quarter strength weekly + Cal-Mag 2.5ml/gal
Vegetative (Week 2-6): Half to full strength + Cal-Mag 5-10ml/gal
Mature (Week 6-8): Full strength weekly + Cal-Mag 10ml/gal
Cut & Come Again (Week 8+): Full strength + Cal-Mag 10ml/gal after each harvest
Plant Density Note
Our hydroponic calculations assume approximately 1.2 plants per gallon of reservoir capacity for leafy greens. For example: 10-gallon system ≈ 12 plants, 25-gallon ≈ 30 plants, 50-gallon ≈ 60 plants, 100-gallon ≈ 120 plants. Adjust based on mature plant size — baby leaf production can support higher densities.
HOW TO USE
Soil & Container Growing
- Dissolve the recommended amount in water (1-2 gallons per application).
- Apply around the base of each plant, avoiding direct contact with leaves to prevent burn.
- Water thoroughly after application to move nutrients into the root zone.
- Apply every 4-6 weeks during the growing season.
- For best results, supplement with Cal-Mag Plus between fertilizer applications to prevent tip burn.
Hydroponic Systems
- Fill your reservoir with water to 80% capacity.
- Add Cal-Mag Plus first and stir thoroughly.
- Add Lettuce Fertilizer 8-15-36 and stir until completely dissolved.
- Check and adjust pH to 5.8-6.2 for mature plants or 6.4-6.7 for seedlings.
- Verify EC/PPM levels match your target growth stage.
- Top off to final volume. Monitor and replace solution every 1-2 weeks.
Foliar Spray
- Dissolve at the recommended concentration in a spray bottle or backpack sprayer.
- Apply early morning or late afternoon to avoid leaf burn.
- Spray both upper and lower leaf surfaces until runoff.
- Repeat every 1-2 weeks during active growth.
- Do not apply during peak sun hours or when temperatures exceed 85°F.
Pro Tip: Preventing Tip Burn in Hydroponic Lettuce
Tip burn is the #1 quality issue in hydroponic lettuce. It's caused by calcium not reaching fast-growing leaf tips. Always add Cal-Mag Plus first, maintain good air circulation around heads, and keep EC below 2.2 during rapid growth. Reducing night temperatures by 5-10°F also helps by slowing growth enough for calcium transport to keep up.
When Lettuce Fertilizer 8-15-36 Is the Right Choice
- Growing any leafy green — lettuce, kale, spinach, chard, bok choy, arugula, collards
- Hydroponic systems (NFT, DWC, ebb and flow, aeroponics) for leafy crops
- Microgreen and baby leaf production at reduced concentration
- Commercial greenhouse lettuce operations at any scale
When to Consider Other Options
- Growing tomatoes or peppers — try Tomato Fertilizer 4-18-38 for nightshade-optimized ratios
- Growing cucumbers or melons — try Cucumber Fertilizer 8-16-36 for vine crop ratios
- Growing strawberries — try Strawberry Fertilizer 8-12-32 for optimized berry nutrition
- Growing herbs that prefer lower nutrient levels — try Pepper & Herb 11-11-40 for herb-friendly ratios
LETTUCE FERTILIZER CALCULATOR
SAFETY & HANDLING
Personal Protective Equipment (PPE)
- Wear gloves and eye protection when handling dry powder or concentrated solutions
- Avoid inhaling dust — use in well-ventilated areas or wear a dust mask when measuring
- Wash hands thoroughly after handling
Storage Guidelines
- Store in a cool, dry place in the original sealed container
- Product is hygroscopic — it will absorb moisture from the air if exposed
- Keep out of direct sunlight and away from heat sources
- If powder clumps from moisture exposure, break it up — efficacy is not affected
- Keep away from children and pets
Application Precautions
- Do not mix dry fertilizer with other products before dissolving in water
- Do not apply foliar sprays during peak sun hours or when temperatures exceed 85°F
- Avoid direct contact with plant leaves when applying concentrated solution to soil
- Water thoroughly after soil application to prevent root burn
First Aid
- Eye contact: Flush with clean water for 15 minutes. Seek medical attention if irritation persists
- Skin contact: Wash affected area with soap and water
- Ingestion: Do not induce vomiting. Contact Poison Control (1-800-222-1222) or seek medical attention
- Inhalation: Move to fresh air. Seek medical attention if symptoms persist
Refer to the Safety Data Sheet (SDS) for complete safety information.
COMPLETE YOUR SYSTEM
Build a complete leafy green feeding program by pairing 8-15-36 with these essential companions.
Cal-Mag Plus 2-0-0
Prevents tip burn and calcium deficiencies. Required supplement for hydroponic lettuce production.
AlternativeCalcium Nitrate 15.5-0-0
Another calcium source option with a small nitrogen boost for the vegetative stage.
BoostChelated Iron EDTA 13%
Extra iron for deep green color and enhanced chlorophyll production in leafy greens.
QualityPotassium Sulfate 0-0-53
Additional potassium for improved texture and extended shelf life before harvest.
FREQUENTLY ASKED QUESTIONS
Why is the potassium (36%) so high in this formula?
Leafy greens consist largely of water, and potassium is the nutrient that controls water pressure inside plant cells (turgor pressure). The 36% potassium delivers thicker cell walls for that perfect crunch, resistance to wilting under grow lights, and significantly longer shelf life after harvest. Without adequate potassium, lettuce becomes limp and loses market value quickly.
What pH should I maintain for lettuce?
Lettuce is particularly sensitive to pH. If pH is too high, iron locks out (causing yellow leaves). If too low, calcium locks out (causing tip burn). For hydroponics, keep pH between 5.8-6.2 for the best balance. In soil, aim for 6.0-6.5. Check pH daily in hydroponic systems — lettuce responds quickly to pH drift.
Will this fix tip burn on my lettuce?
Tip burn is a calcium transport issue — calcium isn't reaching the fast-growing inner leaves quickly enough. This fertilizer does not contain calcium because calcium and phosphorus are chemically incompatible in the same solution. You must supplement with Cal-Mag Plus or Calcium Nitrate. Our balanced formula helps by keeping nitrogen moderate (reducing excessive growth rate) and providing high potassium (improving calcium transport within the plant).
Can I use this for baby leaf and microgreen production?
Absolutely. For baby leaf (3-4 weeks to harvest), use at 50-75% of standard concentration, apply every 5-7 days, and target EC of 0.8-1.2. For microgreens (7-14 days to harvest), use at 25% concentration after cotyledons emerge — a single application is usually sufficient with a target EC of 0.4-0.6.
Why doesn't this fertilizer contain calcium?
Calcium and phosphorus are chemically incompatible in concentrated solution. When mixed, they form insoluble calcium phosphate that precipitates out and becomes unavailable to plants. Since our formula contains 15% phosphorus, calcium must be applied separately. Use Cal-Mag Plus 2-0-0 or Calcium Nitrate 15.5-0-0 as a companion product.
How do I store the powder?
Our fertilizer is highly hygroscopic, meaning it absorbs moisture from the air. Keep the bag sealed tight between uses and store in a cool, dry place out of direct sunlight. If it clumps from moisture exposure, simply break it up — the efficacy is not affected.
What's the role of nitrogen at 8% for leafy greens?
You might expect a leafy green fertilizer to have very high nitrogen, but too much creates problems: overly succulent tissues prone to disease, reduced shelf life, bitter flavors, and increased nitrate accumulation in leaves. Our 8% provides enough nitrogen for healthy chlorophyll production and leaf development without the downsides. For more on nitrogen's role, read our article What's the Function of Nitrogen in Plants?
GROW WITH CONFIDENCE
Important details on quality, returns, sustainability, and charitable efforts that set our product apart.
Product Quality Guaranteed
- Manufactured in Madera, California, USA
- Tested by independent third-party laboratories for purity and guaranteed analysis
- Registered with the California Department of Food and Agriculture (CDFA)
- Independently tested for heavy metal content
- 100% chelated micronutrients (Fe, Mn, Zn, Cu) for maximum bioavailability
Hassle-Free Return Policy
If you're not completely satisfied, we offer a 90-day money-back guarantee. Simply return the unused portion in its original packaging, and we'll process a full refund. No questions asked.
Environmental Responsibility
We're committed to sustainable practices, including:
- Recyclable packaging materials
- Precise nutrient formulation to reduce environmental runoff
- Support for integrated pest management (IPM) practices
- Promoting efficient nutrient delivery systems like hydroponics
Charitable Contributions
1% of all profits go to our foundation, focused on improving educational opportunities for children in agricultural communities.
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