The MaxiGro feeding schedule on the General Hydroponics label is simple: 1–2 teaspoons per gallon of fresh water (5–10 grams per 4 liters). In hydroponics, change the reservoir weekly. In soil, feed once or twice a week with plain water in between. Use mild strength for delicate plants and full strength for robust ones, then switch to MaxiBloom when plants begin flowering or setting fruit.
| Stage or situation | Product | Label rate | How often |
|---|---|---|---|
| Delicate plants, seedlings, clones | MaxiGro 10-5-14 | Mild strength (low end, 1 tsp/gal) | Hydro: change reservoir weekly |
| Robust vegetative growth, salad greens | MaxiGro 10-5-14 | Full strength (up to 2 tsp/gal) | Hydro: change reservoir weekly |
| Soil or container plants | MaxiGro 10-5-14 | 1–2 tsp/gal | Once or twice weekly, plain water between |
| Flowering and fruiting | MaxiBloom 5-15-14 | Follow the MaxiBloom label | Per label |
Rates from the MaxiGro product label, checked October 8, 2026. Always follow the label on your bag.
What Is MaxiGro (and Why the MaxiGro Feeding Schedule Is So Short)?
MaxiGro is a one-part, water-soluble dry nutrient from General Hydroponics. The label says it’s designed “for rapidly growing plants prior to flowering or fruit-set as well as salad greens,” and that it works in hydroponics and soil.
| Guaranteed analysis (label) | Amount |
|---|---|
| Total nitrogen (N) | 10.0% (1.5% ammoniacal, 8.5% nitrate) |
| Available phosphate (P2O5) | 5.0% |
| Soluble potash (K2O) | 14.0% |
| Calcium (Ca) | 6.0% |
| Magnesium (Mg) | 2.0% |
| Sulfur (S) | 3.0% |
| Iron (Fe), chelated | 0.12% |
| Manganese (Mn), chelated | 0.05% |
Because calcium and magnesium are built in, MaxiGro is a true one-part feed. That’s the main reason growers pick it over multi-part programs.
How to Follow the MaxiGro Feeding Schedule: 6 Steps
The MaxiGro feeding schedule is short on purpose. One powder, one rate range and a weekly change. Here’s the practical version.
- Start with fresh water at room temperature.
- Measure the powder. Use 1 tsp per gallon for mild strength or up to 2 tsp for full strength. A gram scale is more consistent than a spoon.
- Dissolve completely before adding any compatible supplements.
- Check pH. General Hydroponics notes a common range of 5.5–6.5 for hydro and soilless systems.
- Check EC so you know what “mild” and “full” mean in your water. See our EC and TDS guide.
- Refresh weekly. The label says to change the hydroponic reservoir every week.
What the MaxiGro Feeding Schedule Means in PPM
The label equates 1 tsp per gallon with 5 grams per 4 liters, or 1.25 g per liter. Using the guaranteed analysis, we calculated what that delivers:
| Label rate | Nitrogen | Potassium (K) | Calcium |
|---|---|---|---|
| 1 tsp/gal (5 g per 4 L) | About 125 ppm | About 145 ppm | About 75 ppm |
| 2 tsp/gal (10 g per 4 L) | About 250 ppm | About 290 ppm | About 150 ppm |
These are our estimates from label percentages, not figures published by General Hydroponics. They show why the top of the range is strong for leafy greens and seedlings. For the formula, see our hydroponic nutrient calculator guide.
MaxiGro Feeding Schedule for Hydroponics vs Soil
The same powder works in both systems, but the MaxiGro feeding schedule changes with how often you apply it.
| Factor | Hydroponics | Soil |
|---|---|---|
| Rate | 1–2 tsp/gal | 1–2 tsp/gal |
| Frequency | Constant feed; change reservoir weekly | Once or twice weekly |
| Between feeds | Top up with water as plants drink | Plain water |
| Watch for | EC creep, pH drift, warm water | Salt buildup, tip burn |
In soil, the plain-water rule matters. Fertilizer salts can build up in pots, so flush occasionally. Our guide to hydroponic nutrients in soil covers the pour-through check.
Who Should Use the MaxiGro Feeding Schedule?
The MaxiGro feeding schedule fits growers who want one bag and one rate range. It’s popular for apartment systems, classroom kits and first hydroponic lettuce crops. If you prefer a multi-part dry program with more fine control, compare it with our Jacks 321 and Masterblend guides.
Beginners often stick with MaxiGro for greens because the MaxiGro feeding schedule doesn’t require separate calcium nitrate bags. Fruiting crops still need the switch to MaxiBloom after vegetative growth.
When to Switch to MaxiBloom
The MaxiGro label says to use it “during the growth phase and switch to MaxiBloom during the bloom phase.” MaxiBloom is 5-15-14. General Hydroponics describes it as a stand-alone dry concentrate for flowering and fruiting plants, and recommends the switch as plants move from vegetative to reproductive growth.
- Tomatoes, peppers, cucumbers: switch as flowers and first fruit appear.
- Lettuce, herbs, greens: many growers stay on MaxiGro the whole crop, since they’re harvested before flowering.
- Photoperiod crops: switch when you change the light schedule to flowering.
Tips for a Better MaxiGro Feeding Schedule
These habits make results more consistent from one reservoir to the next.
- Keep the reservoir cool. General Hydroponics advises keeping solution below about 75°F. See our reservoir temperature guide.
- Feed lighter in heat. GH suggests less concentrated solutions in hotter, brighter or drier conditions.
- Aerate deep water culture reservoirs.
- Test your tap water. Hard water adds calcium and magnesium; see our hard water guide.
- Write it down. Log the teaspoons, EC and pH for each batch.
Common MaxiGro Feeding Schedule Mistakes
- Starting seedlings at full strength.
- Topping up with nutrient instead of water, so EC climbs all week.
- Skipping the weekly reservoir change.
- Mixing MaxiGro and MaxiBloom together “for balance.” Use one or the other per the label.
- Adjusting pH before the powder is fully dissolved.
Storing MaxiGro Powder
Keep the bag sealed, dry and out of direct sun. Humidity makes dry fertilizers clump, which makes spoon measurements even less reliable. Store it away from children and pets, and read the safety directions on the label before handling.
FAQs: MaxiGro Feeding Schedule
How much MaxiGro per gallon?
The label says 1–2 teaspoons per gallon of fresh water, or 5–10 grams per 4 liters.
How often should I use MaxiGro in soil?
Once or twice weekly, with plain water between applications.
Does the MaxiGro feeding schedule need Cal-Mag?
MaxiGro already contains 6% calcium and 2% magnesium. With soft or RO water, some growers add a Cal-Mag supplement; follow that product’s label.
Can I use MaxiGro for the whole grow?
For leafy greens, yes. For flowering and fruiting crops, the label says to switch to MaxiBloom.
Related HydroponicEra Guides
- Flora Series feeding chart
- Best hydroponic nutrients
- Jacks 321 feed chart
- How to use hydroponic nutrients
Sources
- General Hydroponics — MaxiGro 10-5-14
- General Hydroponics — MaxiGro product label (PDF)
- General Hydroponics — MaxiBloom 5-15-14
- Photo credits (Wikimedia Commons, edited with titles): PepperFlower4K by Bst9jkj (CC0); Medals weighed in digital scale by Kpubkalanami (CC BY-SA 4.0); PH- und Leitfähigkeitsmessgeräte by Rotkaeppchen68 (CC0); Greenhouse filled with tomato plants and a bucket on the path by Shixart1985 (CC BY 2.0); Pepper and tomato seedling trays at Boğaziçi University 2026 by Furkan Akkurt (CC BY-SA 4.0)
HydroponicEra is not affiliated with General Hydroponics. Product names are trademarks of their owners.
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