Fox Farm Nutrients for Hydroponics: Cultivation Nation Feed Chart
Fox Farm is arguably the most recognizable brand in the indoor gardening space, famous for their vibrant art and legendary Ocean Forest soil. However, when transitioning from soil to a DWC hydroponic system or a recirculating Dutch bucket hydroponic system, many growers make a critical, crop-destroying mistake: they pour organic soil fertilizers into their water reservoirs.
To use fox farm nutrients for hydroponics successfully, you must bypass their legacy soil products and utilize their specialized, 100% water-soluble Cultivation Nation 3-part mineral line. This system provides the exact same explosive vegetative growth and heavy flowering that Fox Farm is known for, but engineered specifically for sterile, aquatic environments.
Insights Most Growers Overlook
- The “Big Bloom” Trap: Countless beginners buy the classic Fox Farm trio (Grow Big, Tiger Bloom, Big Bloom) thinking it works for hydro. “Big Bloom” contains earthworm castings and bat guano. If you put this organic matter into an oxygen-rich reservoir, it will instantly breed anaerobic bacteria, smell like a sewer, and kill your plants within 48 hours.
- Cultivation Nation pH Drift: The Cultivation Nation line is incredibly stable, but it does cause a sharp initial pH drop when first mixed. Do not chase the pH immediately. Let the reservoir circulate for 30 minutes before adjusting, or you’ll be constantly yo-yoing your pH up and down.
- Micro-Nutrient Lockout: Just like other 3-part systems, the Fox Farm Cultivation Nation Micro bottle must be added to the water first. If it touches the Bloom bottle before being diluted, the calcium and phosphorus will chemically lock into an unusable white chalk at the bottom of your tank.
- The Flushing Phase: Fox Farm nutrients run “hot” (high EC). If you do not perform a pure water flush during the last 5 days of flower, your final harvest will likely have a harsh, metallic taste from excess salt buildup in the plant tissues.
Organic Soil vs. Synthetic Hydroponic Lines
In a traditional soil grow, complex organic compounds (like worm castings or bat guano) are broken down slowly by a vast web of microorganisms and fungi. The plant relies on this biological breakdown to feed.
Hydroponics works entirely differently. A hydroponic reservoir is designed to be a sterile environment where nutrients are delivered in their purest, raw mineral salt form. The plant roots absorb these mineral salts immediately without needing microbes to break them down. If you introduce organics into this warm, highly-oxygenated water, bad bacteria will rapidly consume the organic matter, strip all the dissolved oxygen out of the water, and coat your roots in a thick brown slime (Pythium/Root Rot).
This is why Fox Farm explicitly designed the Cultivation Nation line (Micro, Grow, and Bloom) as a highly refined, 100% water-soluble mineral fertilizer. It provides massive yields for hydroponic tomatoes and demanding indoor crops while keeping your water pump, air stones, and roots perfectly clean.
The Strict Cultivation Nation Mixing Order
Much like the General Hydroponics Flora Series feed chart, Fox Farm’s 3-part hydroponic line demands a very strict sequence of operations. Because the minerals are highly concentrated, they cannot interact with each other in their pure liquid states.
The Golden Sequence:
1. Ensure your reservoir is filled to the final volume with clean water.
2. Shake the Cultivation Nation Micro bottle vigorously. Measure and pour it into the reservoir. Wait 2 minutes for it to fully dilute.
3. Shake and add the Cultivation Nation Grow. Stir vigorously.
4. Shake and add the Cultivation Nation Bloom. Stir vigorously.
5. Wait 10 to 15 minutes before taking any pH readings.
Fox Farm Cultivation Nation Feed Charts
| Growth Phase | Part 1: Micro | Part 2: Grow | Part 3: Bloom | Target EC (mS/cm) |
|---|---|---|---|---|
| Seedling / Rooting | 2 ml | 2 ml | 2 ml | 0.5 – 0.7 |
| Early Vegetative (Week 2) | 5 ml | 5 ml | 5 ml | 0.9 – 1.2 |
| Peak Vegetative (Week 4) | 8 ml | 10 ml | 4 ml | 1.4 – 1.8 |
| Early Flower (Transition) | 8 ml | 8 ml | 8 ml | 1.5 – 1.9 |
| Peak Flower (Fruit Swelling) | 8 ml | 2 ml | 12 ml | 1.8 – 2.2 |
| Late Flower Ripening | 6 ml | 0 ml | 16 ml | 1.6 – 1.9 |
| Final Flush (Pre-Harvest) | 0 ml | 0 ml | 0 ml | 0.0 – 0.2 |
Modifying the Chart for Coco Coir and RO Water
If you are growing in coco coir hydroponics, you face a unique challenge: the coco fibers act like a magnet for Calcium and Magnesium. If you strictly follow the chart above, your plants will rapidly develop rusty brown spots on their leaves (calcium deficiency) because the coco coir will steal the calcium from the Micro bottle before the plant can eat it.
To counter this, you must supplement the Fox Farm line with a Cal-Mag product. Additionally, if you use Reverse Osmosis (RO) water that has been stripped of its natural minerals, you must also add Cal-Mag. Always dose 3 to 5ml of Cal-Mag per gallon into the reservoir before adding the Cultivation Nation Micro.
| Growth Stage | Cal-Mag Additive | Micro | Grow | Bloom |
|---|---|---|---|---|
| Vegetative Growth | 5 ml | 8 ml | 10 ml | 4 ml |
| Transition (Week 1 Flower) | 5 ml | 8 ml | 8 ml | 8 ml |
| Peak Bloom | 3 ml | 8 ml | 2 ml | 12 ml |
| Late Ripening | 0 ml | 6 ml | 0 ml | 16 ml |
| Flush | 0 ml | 0 ml | 0 ml | 0 ml |
Hitting Your pH and EC Targets
Once you mix your Fox Farm nutrients, you must measure the electrical conductivity (EC) to ensure the solution is not too strong. Use a hydroponic nutrient calculator to check your targets against your specific plant’s needs. The Cultivation Nation line is very strong, so if your EC spikes above 2.2 during flower, you should dilute the tank with fresh water to prevent tip burn.
Finally, execute strict pH management. Utilize a pH calculator and adjusting solutions to lock the reservoir in at exactly 5.8 to 6.2. At this pH range, every single mineral in the Fox Farm mineral profile is bio-available to the roots.
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Frequently Asked Questions
Written by Sarah Collins
Sarah Collins is a hydroponic grower and horticultural researcher with 8+ years of hands-on experience in DWC, NFT, recirculating, and soil systems. She designs tools and publishes guides at currentgardening.com to help indoor growers optimize their yields.
