Trace Minerals & Magnesium for Plants

Leaves going yellow between the veins is one of the most misread signs in growing. It can point to low magnesium or a short trace element, and it can just as easily be overwatering, a pH problem or a plain old leaf. This is a practical rundown of what magnesium and micronutrients do, how to read the clues, and where Vitamin Sea, our 0-0-0 soil amendment, does and does not fit.

Quick Answer: What Vitamin Sea Is and Isn't

Vitamin Sea is not a fertilizer. It is a concentrated seawater extract with 95% reduced sodium, and we classify it as a soil amendment. The label grade is 0-0-0, and the guaranteed analysis is magnesium 3.00% and boron 0.02%.

Is it a fertilizer? No. It has no N-P-K guarantee and does not replace your regular feed.
How much do I dilute? 1 tsp (5 ml) per gallon of water. Never apply it undiluted.
How often? Every 3 to 4 weeks, as a foliar spray or a soil drench.
Can I use it in flowering? Yes. Our program uses it through veg and bloom.

We don't describe Vitamin Sea as plant food. States draw the line between "fertilizer" and "soil amendment" in different places, so read the label and not the category name. If the classification matters to you, ask your state department of agriculture or your certifier.

What Micronutrients Do

Plants need about 17 essential elements. Carbon, hydrogen and oxygen come from air and water. Nitrogen, phosphorus and potassium are the primary nutrients, and calcium, magnesium and sulfur are the secondary ones. The rest are the micronutrients: iron, manganese, zinc, copper, boron, molybdenum, chlorine and nickel.

Plants need micronutrients in tiny amounts, and many work as enzyme cofactors, the helper minerals an enzyme needs to do its job. Iron, manganese, zinc, copper and molybdenum turn up in enzymes tied to photosynthesis, respiration and nitrogen handling. Boron helps build cell walls and move sugars.

Magnesium is technically a secondary nutrient, but it belongs here because Vitamin Sea guarantees it next to boron. It sits at the center of every chlorophyll molecule and helps activate many enzymes.

A plant is limited by whatever it has the least of, so plenty of N-P-K does not help if one trace element is short. That said, in most garden soils that get regular compost and sit at a reasonable pH, trace-element gaps are not the first thing to go wrong. They are more likely in sandy soil, high-pH soil and some potting mixes, and magnesium can leach out of sandy soil and containers with heavy watering.

Signs of Low Micronutrients

Leaf color is the usual first clue, and it is a weak one. Yellowing between the veins, called interveinal yellowing, can be a sign of low magnesium or a low trace element. It can just as easily be a sign of overwatering, poor drainage, damaged roots, cold soil, a pH problem or a leaf that is simply old.

Magnesium moves around inside the plant, so a shortfall tends to show on older, lower leaves first. Iron, manganese and zinc move less, so shortfalls tend to show on new growth first.

Clues, Not a Diagnosis

Yellow between green veins on older, lower leaves. Can be a sign of low magnesium. Rule out leaf age, overwatering and a pH problem first.
Yellow between green veins on the newest leaves. Can be a sign of low iron, manganese or zinc. Rule out high pH, soggy or damaged roots and cold soil first.
Small, stunted or distorted new growth despite adequate N-P-K. Can be a sign of low zinc or boron, among other things. Rule out root trouble, water stress and heat first.

A lab soil test tells you more than leaf color does. Ask for magnesium and micronutrients, since they are not always in the basic panel. If pH is the suspect, our piece on managing soil pH organically is the place to start.

Dose and Application

Vitamin Sea is a concentrate. The label leads with a must-dilute caution and also carries a boron caution. Boron is a trace element with a narrow gap between enough and too much for many plants, so measure, and do not double the dose.

Dilution: 1 tsp (5 ml) per gallon of water.
Method: Foliar spray or soil drench.
Frequency: Every 3 to 4 weeks.
Stage: Veg and bloom.
One 16 fl oz bottle: About 94 gallons of mix.
Mixing: Apply alone. Never mix with synthetic fertilizers, pesticides or herbicides.

For other volumes, scale straight up: 2 gallons takes 2 tsp (10 ml), and 5 gallons takes 5 tsp (25 ml). The Growganica feeding chart is the source of truth for dosage. There is no separate flowering rate, so use the same dose and spacing through veg and bloom. We don't publish rates for particular crops or seedlings, or a last-application date before harvest.

What to Do

Check the basics first. Look at drainage and watering, root health and soil pH, and note whether the symptom starts on older leaves or on new growth.
Measure the dose. If you decide to try Vitamin Sea, put 1 tsp (5 ml) into each gallon of water. Never use it straight from the bottle.
Spray or drench. For a foliar spray, test a few leaves first and wait a day or two. Then spray in the early morning or evening, out of hot sun, until the leaves are wet but not dripping. For a drench, use the mix in place of a normal watering.
Wait before repeating. Leave the full 3 to 4 weeks. Leaves that have already yellowed usually do not turn green again, so judge the result by new growth.
Keep it on its own. Do not mix it into the same container as synthetic fertilizers, pesticides or herbicides, and leave a few days between them and Vitamin Sea.
Keep your regular feed going. Vitamin Sea does not replace it.

Our product notes suggest a foliar application when plants show signs like interveinal yellowing, or stunted growth despite adequate N-P-K. Treat that as something to try, not a promise that the symptom will clear.

Where Growganica Fits

Vitamin Sea is a Step 3 (Power Up) add-on in our three-step program. Step 1 is Microbes (Inoculate), our living-soil product, and Step 2 is Veg or Bloom (Feed). Veg and Bloom need Microbes to work as designed. They list Vitamin Sea as a recommended pairing, not a required one. The whole sequence is laid out on the system page, and how to grow like Growganica walks through it.

Microbes is also the pairing we recommend for Vitamin Sea. The logic, from our product notes: soil microbes release chelating compounds for minerals like iron and zinc, and trace minerals are cofactors for microbial enzymes. You can read more on the product pages for Vitamin Sea and Microbes.

Vitamin Sea makes sense if you want to cover magnesium and trace minerals on a schedule, or if your setup makes gaps more likely, such as a potting mix, sandy soil or high-pH soil. If your plants look healthy and you are not chasing a mineral gap, you can leave it out. It will not fix a pH, watering or drainage problem.

Our product notes count 70 or more trace minerals and other compounds in the concentrate. Seawater also carries a lot of sodium, which is hard on most plants, so the sodium is reduced by 95%. Reduced is not removed, so dilute it as directed. Plant-by-plant feeding schedules are on the feeding schedule page.

Frequently Asked Questions

Is Vitamin Sea a fertilizer?

No. It has no N-P-K guarantee, the label grade is 0-0-0, and we classify it as a soil amendment. It does not replace your regular feed. States draw the line between fertilizer and soil amendment in different places, so read the label, not the category name. If the classification matters to you, for example on a certified plot, ask your state department of agriculture or your certifier.

How much Vitamin Sea do I dilute per gallon?

1 tsp (5 ml) per gallon of water. It is a concentrate, so never apply it undiluted. For other volumes, scale straight up: 2 gallons takes 2 tsp (10 ml), and 5 gallons takes 5 tsp (25 ml). One 16 fl oz bottle makes about 94 gallons of mix. The Growganica feeding chart is the source of truth for dosage.

Can I use Vitamin Sea during flowering?

Yes. Our program uses it through veg and bloom, at the same dose and spacing in both. There is no separate flowering rate. We don't publish rates for particular crops or seedlings, or a last-application date before harvest.