What's the Function of Potassium (K) in Plants?
•Posted on November 30 2016
Last updated: March 25, 2026
Written by: Amir Tajer, B.S.M.E., QAL — Co-Owner & Technical Director, Greenway Biotech
Reviewed against: UC Davis Plant Sciences, Penn State Extension, and University of Minnesota Extension plant nutrition guidelines
Disclosure: Greenway Biotech manufactures potassium fertilizers mentioned in this guide. Multiple potassium sources are compared so you can choose what works best for your situation.
⚡ Quick Facts: Potassium (K) in Plants
- Classification: Primary macronutrient (NPK); plants absorb K in amounts comparable to nitrogen
- Form absorbed: Potassium ion (K⁺) — the most abundant cation inside plant cells
- Key roles: Stomatal regulation, enzyme activation (60+ enzymes), phloem loading, protein synthesis, and stress tolerance
- Deficiency symptom: Marginal leaf scorch (yellowing/browning at leaf edges), starting on older/lower leaves first
- Soil abundance: Makes up approximately 2.1% of the Earth's crust by weight — but plant-available K varies widely by soil type
- Common potassium fertilizer options: Potassium Sulfate 0-0-53, Potassium Chloride 0-0-62, and MKP 0-52-34
- Why potassium is often called a "quality nutrient": Adequate K is closely associated with fruit size, sugar transport, firmness, flavor development, and shelf life in many fruiting crops
Potassium is the third number on any fertilizer bag — and often one of the least understood. While nitrogen gets credit for green growth and phosphorus for roots and blooms, potassium plays a central behind-the-scenes role in plant physiology. It keeps your plants hydrated, powers their energy systems, supports stress tolerance, and strongly influences fruit firmness, sugar movement, and overall eating quality.
Unlike nitrogen, which plants use to build tissue, potassium isn't a structural component at all. It works as an ionic regulator — a kind of biological traffic controller that opens and closes gates, activates enzymes, and keeps water and sugars moving through the plant's vascular system. When K is short, everything slows down.
This guide covers what potassium actually does in plants, how plants take it up, what deficiency looks like (and how to correct it), and which potassium fertilizers work well in different situations — from raised beds to hydroponics to high-value fruit crops.
🌿 Potassium in Plants at a Glance
- Absorbed as the potassium ion (K⁺) from soil water
- Regulates stomatal opening and closing, controlling water use and CO₂ intake
- Required for the activity of 60+ plant enzymes
- Helps move sugars from leaves into developing fruit
- Supports drought, cold, and disease tolerance
- Deficiency appears first on older, lower leaves — yellowing or scorching at the margins
What Is Potassium and Where Does It Come From?
Potassium is a primary macronutrient and an abundant mineral element present in both plant and animal tissues. It is essential for the proper function of all living cells — which is why it appears in the NPK ratio on every bag of fertilizer you've ever purchased.
In the Earth's crust, potassium makes up roughly 2.1% by weight, making it one of the more plentiful elements overall. However, it doesn't exist in pure form in nature. It occurs naturally in mineral compounds including sylvite (KCl), carnallite, langbeinite, and other evaporite deposits. These minerals — collectively referred to as "potash ores" in the mining industry — are processed into the agricultural and horticultural fertilizers used today.
In soil, potassium exists in four pools: dissolved in soil water (immediately plant-available), exchangeable on soil particle surfaces (the primary plant-available reservoir), non-exchangeable in mineral structures (slowly released over time), and mineral-bound in primary rock minerals (essentially unavailable in the short term). The dissolved and exchangeable fractions are what plants draw on during the growing season[1].
🔬 Did You Know?
Potassium is the most abundant cation (positively charged ion) inside plant cells. While it makes up about 2.1% of the Earth's crust, the concentration inside a plant cell can be 100 times higher than in the surrounding soil solution — plants actively pump and concentrate it[1].
How Plants Absorb Potassium
Plants absorb potassium exclusively as the potassium ion (K⁺). This ion moves from the soil solution into root cells through specialized membrane channels and protein carriers — a process that requires energy in the form of ATP[2]. This is why anything that impairs root respiration (waterlogged soil, compaction, cold temperatures) can reduce potassium uptake even when soil K levels appear adequate.
Once inside the root, K⁺ moves through the plant's xylem — the water-conducting tissue — reaching leaves, stems, and fruit. Potassium is also highly mobile in the phloem, the tissue responsible for transporting sugars. This mobility allows the plant to redistribute potassium from older tissue to newer growth when supply is limited, which is why potassium deficiency typically shows on older leaves first.
Several factors can limit potassium uptake even when soil levels seem adequate:
- High soil pH: Above pH 7.5–8.0, elevated calcium and magnesium levels often compete with K⁺ at root absorption sites, reducing the amount of potassium plants can take up even when soil K levels appear adequate
- Competing cations: Even at moderate pH, excess calcium, magnesium, or ammonium can compete with K⁺ at root uptake sites, reducing effective absorption
- Sandy soils: Low cation exchange capacity means K leaches quickly in high-rainfall areas
- Cold soil temperatures: Root metabolism slows, reducing energy available for active ion uptake
- Compaction or waterlogging: Poor aeration reduces root respiration and ATP availability[3]
Potassium is also made available through fertilizers in the form of K₂O (potassium oxide), which is the standard reporting unit on fertilizer labels. When dissolved in water or soil moisture, these compounds release K⁺ ions that plants can directly absorb.
💡 The Manganese-Potassium Connection
Adequate manganese supports root enzyme activity and overall plant metabolism, which may indirectly support potassium uptake and utilization in some situations. When manganese is deficient, K uptake may be affected even if soil K levels appear adequate. See our article on the relationship between manganese and potassium for more on this connection.
What Is the Function of Potassium in Plants?
Potassium doesn't build plant tissue the way nitrogen and phosphorus do. Instead, it functions as an ionic regulator and enzyme activator — controlling dozens of biochemical processes simultaneously. Plants cannot substitute any other element for potassium in these roles, making it truly indispensable.
Here are the primary functions of potassium in plant physiology:
Stomatal Regulation and Water Use Efficiency
Guard cells control the opening and closing of stomata — the microscopic pores on leaf surfaces through which CO₂ enters and water vapor exits. Guard cells open and close by pumping K⁺ in and out to change their osmotic pressure and shape. Well-supplied plants maintain precise stomatal control, improving water use efficiency and reducing wilting under heat or drought stress[2].
Enzyme Activation
Potassium is required for the activity of more than 60 plant enzymes involved in protein synthesis, starch formation, and energy metabolism[4]. These enzyme systems are so K-specific that no other ion can substitute, which is why potassium deficiency affects so many plant processes at once.
Phloem Loading and Sugar Transport
Photosynthesis produces sugars in leaves, but those sugars need to travel to developing fruits, seeds, and roots. Potassium drives the active loading of sucrose into the phloem (the plant's sugar transport highway). Potassium-deficient plants often accumulate sugars in their leaves rather than partitioning them to harvest organs — which directly explains why low-K crops tend to produce smaller, less sweet fruit[2].
Protein and Starch Synthesis
Potassium is required for both protein and starch synthesis in plant cells. It helps stabilize the ribosome structure needed for protein assembly, and activates the enzymes that link glucose molecules into starch chains. This is particularly important for root crops like potatoes, which depend heavily on starch accumulation[1].
Nutrient and Water Transport
Beyond sugar transport, potassium plays a central role in overall osmoregulation — the management of water and dissolved nutrients across cell membranes. It helps maintain the turgor pressure that keeps plant cells rigid and functional, and it facilitates the movement of other nutrients from roots through stems to leaves.
Stress Tolerance
Adequate potassium supports disease resistance through several mechanisms: better stomatal control limits the entry points available to airborne pathogens, improved turgor pressure keeps tissues firm, and well-supplied plants produce defensive compounds more efficiently. Potassium also increases solute concentration in plant cells, lowering the freezing point and protecting tissues from cold damage. Plants with adequate K supply typically show improved tolerance to drought, cold, and disease pressure[5].
🔬 Did You Know?
Potassium is required for the activity of more than 60 plant enzymes involved in protein synthesis, starch formation, and energy metabolism. Many of these enzyme systems are so K-specific that no other ion can substitute — which is why potassium deficiency affects so many plant processes simultaneously[4].
Potassium and Fruit Quality
Potassium is often called a "quality nutrient" — and it earns that reputation most clearly in fruiting crops. High-carbohydrate fruits like tomatoes, strawberries, potatoes, and peppers rely heavily on adequate potassium to help move sugars from leaves into developing fruit. The fruit functions as a storage sink for both sugars and potassium simultaneously, which is why K demand rises sharply at fruit set[6].
What adequate potassium is often associated with in fruiting crops:
- Higher Brix levels: More sugar transported to fruit is associated with better flavor and sweetness
- Improved firmness: Better cell turgor and integrity can help fruit hold up longer post-harvest
- More uniform sizing: Consistent potassium supply supports even cell expansion across developing fruit
- Improved stress tolerance: Better stomatal control and turgor pressure can reduce wilting and disease vulnerability
- Better cold tolerance: Higher solute concentration in cells lowers the freezing point and may protect fruit from late frosts
This is why high-K specialty fertilizers like Strawberry Fertilizer 8-12-32, Tomato Fertilizer 4-18-38, and Lettuce Fertilizer 8-15-36 are formulated with elevated potassium ratios — the nutritional demand during fruit set and fill is significant.
💡 Potassium Demand Peaks at Fruit Set
Potassium uptake in fruiting crops isn't constant throughout the season. Demand typically ramps up significantly at fruit set and continues through fill and ripening. For soil-grown crops, it's worth applying a potassium-rich fertilizer as flowers begin to open — not just at planting. For hydroponic growers, this is the time to shift to a higher-K nutrient formula.
Before You Apply Potassium Fertilizer
While potassium deficiency is common, not every garden or crop actually needs additional K. Blindly applying potassium fertilizer to K-rich soil doesn't benefit plants and can create ion imbalances that interfere with calcium and magnesium uptake. The best starting point is always a soil test.
| Your Situation | Recommended Approach |
|---|---|
| Haven't soil tested | Apply a moderate rate (1 lb/100 sq ft) of a complete fertilizer; soil test after first season |
| Soil test shows K below 100 ppm | Apply potassium fertilizer at full recommended rate before planting |
| ⭐ Soil test shows K 100–200 ppm | Moderate maintenance rate (0.5–1 lb K₂O/100 sq ft); prioritize high-K crops like tomatoes and berries |
| Soil test shows K above 200 ppm | Skip standalone K application; use a balanced NPK formula only |
| Sandy soil in high-rainfall area | Split applications (at planting + mid-season) reduce leaching losses |
| Growing fruiting crops (tomatoes, berries) | Increase K at fruit set; use high-K specialty formula |
| Hydroponic system | Use water-soluble K sulfate or MKP; avoid chloride sources for sensitive crops |
| Chlorine-sensitive crops (strawberries, potatoes) | Use Potassium Sulfate 0-0-53 rather than Potassium Chloride |
💡 A Soil Test Pays for Itself
A $15–30 soil test reveals your actual K status before you spend money on fertilizer. UC Cooperative Extension and most state land-grant universities offer basic soil tests through their county offices. Testing at the same time each year also lets you track whether your fertilization program is moving the needle over time.
Potassium Deficiency in Plants
Despite potassium's relative abundance in most soils, deficiency is common — particularly in sandy soils, high-rainfall regions, or intensive cropping systems where K is removed in large amounts with each harvest. Deficiency tends to develop gradually, and early symptoms are subtle enough to miss until significant yield damage has already occurred.
Because potassium is mobile in the plant, the symptoms start on the oldest, lowest leaves first — the plant sacrifices older tissue to keep new growth supplied. This is an important diagnostic clue that distinguishes K deficiency from calcium or sulfur deficiency, which appear on younger growth.
Common potassium deficiency symptoms include:
- Marginal chlorosis (leaf scorch): Yellowing, then browning, along the outer margins of older leaves. The interior of the leaf typically stays green longer, creating a distinctive "scorched edge" appearance.
- Necrotic leaf edges: In advanced deficiency, the yellowed margins die back and may crumble. Leaves may curl inward at the edges.
- Stunted growth: Internodes shorten, stems weaken, and overall plant size is reduced. Root systems are typically underdeveloped.
- Poor fruit size and quality: Fruit tends to be smaller, softer, and less sweet than expected. Tomatoes may show irregular ripening.
- Reduced stress tolerance: Plants wilt more quickly under drought, are more susceptible to frost, and show increased vulnerability to fungal diseases.
⚠️ Don't Confuse K Deficiency with Drought Stress
Potassium deficiency and drought stress produce overlapping symptoms — wilting, leaf scorch, poor growth. Since K helps regulate stomatal function and water use, a K-deficient plant is also more prone to drought stress. If your plants are wilting and showing leaf scorch despite regular watering, K deficiency is worth investigating. A quick soil test is the only way to know for certain.
Diagnosing Potassium Problems
Most potassium issues show visible symptoms before significantly affecting yield — if you know what to look for. The table below covers the most common problems and how to address them. Keep in mind that multiple deficiencies can occur simultaneously, and a soil test is the definitive diagnostic tool.
| Symptom | Likely Cause | Recommended Action |
|---|---|---|
| Yellowing/browning at leaf margins, older leaves first | Classic K deficiency | Apply water-soluble K fertilizer; soil test to confirm; address pH if above 7.5 |
| ⭐ Leaf scorch despite adequate soil K on soil test | K tied up by high pH, Ca, or Mg; poor root uptake | Adjust soil pH toward 6.0–7.0 if below 5.5 or above 8.0; address Ca/Mg cation competition; check soil drainage and compaction |
| Small fruit, low Brix, soft texture at harvest | Insufficient K during fruit fill stage | Apply high-K fertilizer at fruit set; use 0-0-53 or high-K specialty formula |
| Weak stems, lodging in grain crops | K deficiency limiting cell wall strength | Apply K before heading; use foliar K as emergency correction |
| Increased disease pressure (powdery mildew, blight) | Low K reduces cell wall integrity and plant immunity | Correct K deficiency as part of improving plant resilience; manage disease directly with approved controls as needed |
| Interveinal chlorosis on young leaves (not old leaves) | Likely manganese or iron deficiency — NOT potassium | Test for micronutrient deficiency; apply Chelated Manganese EDTA or Chelated Iron EDTA |
| Uniform yellowing on youngest growth only | Likely sulfur or iron deficiency — NOT potassium | Soil test; K deficiency always starts on OLD leaves, never young growth |
💡 Pro Tip: Photograph Symptoms Before Treating
Take clear photos of symptomatic leaves before applying any corrective treatment. If the issue doesn't resolve within 2–3 weeks, send photos along with your soil test results to your local university extension office for a free consultation. Many states offer plant disease clinics during the growing season.
How to Choose the Best Potassium Fertilizer for Your Plants
Several water-soluble potassium fertilizers work well for home gardens, raised beds, and hydroponic systems. The right choice depends on your crop, your soil, and whether you're also managing for chlorine sensitivity or secondary nutrient needs.
| Product | K₂O % | Secondary Nutrient | Best For |
|---|---|---|---|
| ⭐ Potassium Sulfate 0-0-53 | 53% | 17% Sulfur | Fruit crops, chloride-sensitive plants, hydroponics |
| Potassium Chloride 0-0-62 | 62% | — | Field crops, grains, cost-effective general use |
| Monopotassium Phosphate 0-52-34 | 34% | 52% Phosphorus | Root development, flowering stage, hydroponics |
| K-Mag 0-0-22 | 22% | 11% Mg, 22% S | Crops needing both K and Mg; organic-compatible |
🌱 A Strong Option: Potassium Sulfate 0-0-53
Potassium Sulfate is commonly preferred for fruit crops, berries, and hydroponic systems — it delivers 53% K₂O and 17% sulfur with no chloride, and it's 100% water-soluble. For chloride-sensitive crops like strawberries, tomatoes, and peppers, K sulfate is often a good choice over potassium chloride.
Shop Potassium Sulfate 0-0-53🌱 For Fruiting Stage: Specialty High-K Formulas
If you're growing tomatoes, strawberries, cucumbers, or peppers, a specialty formula pre-balanced for fruiting stage nutrition is often more practical than mixing standalone fertilizers. These include all micronutrients in a single application.
Tomato Fertilizer 4-18-38 · Strawberry Fertilizer 8-12-32 · Pepper & Herb 11-11-40 · Cucumber Fertilizer 8-16-36
Or browse the full Potassium Fertilizers collection to compare all available options.
Browse Specialty FertilizersHow to Apply Potassium Fertilizer: Rates and Instructions
The instructions below cover Potassium Sulfate 0-0-53 as a standalone potassium amendment. Always adjust based on your soil test results. If you're using a complete specialty fertilizer (tomato, strawberry, etc.), follow the rates on that product's label instead.
For Raised Beds and Garden Soil
Mix: 1 tablespoon (approximately 10–12 grams) per gallon of water
Apply: 1 gallon of solution per 4–6 square feet of bed area
Dose received: Approximately 10–12 grams per 4–6 sq ft
Coverage: One gallon of mixed solution covers a 4–6 sq ft raised bed section
Frequency: Every 4–6 weeks during the active growing season, or as indicated by soil test
For Container Plants
Mix: 1 teaspoon (approximately 4 grams) per gallon of water
Apply: Water to runoff — approximately 1 cup (8 fl oz) per 1-gallon container; scale up proportionally for larger pots
Dose received: Approximately 0.5–1 gram per 1-gallon container
Coverage: One gallon of mixed solution treats approximately 16 one-gallon containers
For Hydroponic Systems
Mix: Per your nutrient calculator target for K ppm — typical working ranges are 150–300 ppm K during vegetative growth and up to 350–400 ppm during fruiting, though targets vary by crop, cultivar, water source, and full nutrient formula
Apply: Add to reservoir after balancing other macro nutrients; check EC and pH after mixing
Target pH: 5.5–6.5 (fruiting crops typically perform well at the lower end during fruit set)
⚠️ Don't Apply Dry Fertilizer Directly to Roots
Potassium sulfate and other soluble K sources should always be fully dissolved in water before applying near plant roots. Direct contact with concentrated fertilizer can cause salt burn. For granular soil applications, broadcast evenly and water in thoroughly immediately after.
💡 When to Consult Your Extension Office
The rates in this guide are generalized for home gardens, raised beds, and common hydroponic use cases. For field-scale production, persistent nutrient problems, or unusual soil conditions, confirm rates with a tissue or soil test and contact your local university extension office for crop-specific guidance. Most county offices offer free or low-cost consultations during the growing season.
🔬 Did You Know?
High-carbohydrate fruit crops like tomatoes, potatoes, and strawberries demand significantly more potassium than leafy greens or herbs. Research suggests the fruit itself functions as a potassium storage sink during fill — which is why K demand peaks at fruit set, not earlier in the season[6].
🎯 Key Takeaways
- Potassium is a primary macronutrient absorbed as K⁺ ions — it's the most abundant cation inside plant cells and drives dozens of essential processes
- K's main roles include stomatal regulation (water use efficiency), activity of 60+ enzymes, phloem loading (sugar transport to fruit), protein and starch synthesis, and stress tolerance
- Deficiency symptoms start on older, lower leaves — marginal yellowing and scorching are the classic signs; young leaf symptoms indicate a different deficiency
- Even adequate soil K can be unavailable if pH is too high, Ca/Mg levels are excessive, or soils are compacted; a soil test helps identify the actual cause
- For fruit crops, Potassium Sulfate 0-0-53 is often a strong choice over Potassium Chloride for chloride-sensitive fruit crops — it's chloride-free and provides beneficial sulfur
- High-K specialty formulas like Tomato Fertilizer 4-18-38 and Strawberry Fertilizer 8-12-32 are formulated for peak fruiting demand
- For hydroponic systems, MKP 0-52-34 and Potassium Sulfate are two commonly used chloride-free potassium sources
- Adequate manganese supports potassium uptake — if K deficiency persists despite fertilization, consider testing manganese levels as well
❓ Frequently Asked Questions
What does potassium do for plants?
Potassium helps plants regulate water through stomatal opening and closing, supports the activity of 60+ enzymes involved in protein and starch synthesis, moves sugars from leaves into developing fruit, and helps improve tolerance to drought, cold, and disease. It is absorbed as the potassium ion (K⁺) and is the most abundant cation inside plant cells. Unlike nitrogen and phosphorus, potassium is not a structural component — it acts as an ionic regulator that keeps dozens of processes running simultaneously.
What does potassium deficiency look like in plants?
Potassium deficiency typically shows as yellowing or browning along the outer edges (margins) of older, lower leaves — a pattern called "marginal chlorosis" or "leaf scorch." The center of the leaf usually stays green longer. As deficiency progresses, the margins may turn brown and die. Stunted growth, weak stems, and poor fruit quality are also common. Because potassium is mobile in the plant, symptoms appear on older tissue first — if you're seeing symptoms on young leaves, it's likely a different deficiency (iron, sulfur, or calcium).
Is potassium sulfate good for plants?
Potassium Sulfate 0-0-53 is a strong choice for most garden, raised bed, and hydroponic applications. It delivers 53% K₂O and 17% sulfur in a chloride-free, 100% water-soluble form — which makes it particularly useful for chloride-sensitive crops like strawberries, tomatoes, peppers, and potatoes. The sulfur component also supports enzyme function and, in alkaline soils, can help improve nutrient availability. It tends to be more expensive per unit of K than potassium chloride, but for fruit crops and hydroponic systems the chloride-free advantage is usually worth it.
What is the difference between potassium sulfate and potassium chloride?
Both supply potassium (expressed as K₂O), but they differ in their secondary component and best-fit crops. Potassium Sulfate 0-0-53 is chloride-free and includes 17% sulfur — commonly preferred for chloride-sensitive crops and hydroponic systems where chloride can accumulate. Potassium Chloride 0-0-62 is more concentrated (62% K₂O) and more cost-effective, making it a practical choice for field crops and grains where chloride sensitivity is less of a concern.
How do plants absorb potassium from the soil?
Plants absorb potassium exclusively as the potassium ion (K⁺) from soil water. This process requires energy (ATP) produced by root cell respiration, which is why anything that compromises root oxygen supply — waterlogging, compaction, cold soil — can reduce K uptake even when soil levels appear adequate. Once inside root cells, K⁺ moves through the xylem to all plant organs and is highly mobile within the plant, allowing redistribution from older to newer tissue when supply is limited.
Can too much potassium hurt plants?
Yes — excess potassium can cause problems. Very high K levels can competitively inhibit calcium and magnesium uptake (since all three are cations competing for the same absorption sites), potentially causing secondary deficiencies. It can also raise soil salt concentration, contributing to tip burn or root salt stress in sensitive plants. This is why a soil test before fertilizing is valuable — K deficiency is not universal, and some soils already have adequate or excess levels.
Why does my soil test show adequate potassium but my plants still show deficiency symptoms?
Several factors can make soil K unavailable even when test levels appear adequate. Above pH 7.5–8.0, elevated calcium and magnesium levels compete with K⁺ at root absorption sites. Poor drainage and compaction limit root respiration and active ion uptake. Cold soil temperatures slow the entire process. Low manganese levels may also affect K uptake indirectly. Addressing pH and drainage first often resolves apparent K deficiency without additional potassium applications.
When should I apply potassium fertilizer?
For most garden crops, a pre-plant or early-season potassium application establishes a good baseline, followed by a second application at or just before fruit set for fruiting crops. Potassium demand tends to be highest during active fruit fill and ripening. For perennials and fruit trees, a late-season application can help support cold tolerance and next year's bud development. Sandy soils in high-rainfall climates benefit from split applications to reduce leaching.
📚 Sources
- Potassium for Crop Production — Penn State Extension
- Potassium for Crop Production — University of Minnesota Extension
- Managing Potassium for Crop Production — Penn State Extension
- Potassium Functions in Plants — International Plant Nutrition Institute
- Assessing and Managing Potassium Concentration — Penn State Extension
- Banking Potassium: Getting Ahead on Tomato Consumption — Penn State Extension
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Leave a CommentTHANKS FOR PROVIDING YOUR VALUABLE INFORMATION TO US
Thanks so much wish to be in touch with you every day.
Alma: Thank you for your questions! Fig trees do need potassium, since it flowers like all fruit plants. Potassium is present in certain fertilizers. We actually have quite a few available that you can browse in our online store. Monopotassium Phosphate is always a good choice. You can apply this product every few weeks to your tree. For additional questions or concerns, please reach out to our customer service team via email and we’d be happy to help! Thank you!
Do fig trees need potassium ? How does one purchase potassium ? When and how often should it be applied to the tree.? What products are save to use ?
senait: Hi there, thank you for your question. Potassium is important for fruit setting. This is because it encourages healthy blossoms in flowering plants (all fruit plants). The flowers become the fruit, so if they don’t blossom correctly or they’re sickly, your fruit will not be as healthy as they could be. Potassium is also responsible for ensuring your fruits form to their fullest so they are more robust come harvest time. We hope this helps! Please let us know if you have any other questions or concerns.
Is potassium very essential for fruit setting?how?