Why You Will Love This

This is the overnight jar that lives on my counter from March onward: four of the herbs traditionally called nourishing or mineral-rich, left in cold water while I sleep. The cold-brew method is the whole trick. Heat pulls tannins out of nettle and oatstraw and turns the cup harsh, and cold does not. What you get instead is a pale green iced tea that tastes slightly sweet, grassy, and clean, like the smell of a field in the evening. Pour it over ice in the afternoon with a slice of lemon and it is one of the few genuinely refreshing things that is not sugar.

The Story Behind It

Herbalists have used overnight infusions of nettle and oatstraw for generations, and the whole point of the tradition is patience: a big jar, a long soak, and drinking it steadily rather than expecting anything from a single glass. This recipe comes straight out of that lineage and adds two things. Lemon balm, because it is the classic evening herb and it makes the blend taste like something rather than like a lawn. Red raspberry leaf, because it rounds the flavour and stops the oatstraw going flat. I start the routine in March, when the days stretch out and the schedule gets busier than the body has caught up with.

Mason jar filled with magnesium herbal iced tea showing nettle, oatstraw, lemon balm, and red raspberry leaf steeping in filtered water with condensation on glass
The overnight cold-brew method draws the herbs out slowly and without heat, which is why the finished tea is mild and slightly sweet instead of astringent.

What You Will Need

  • 2 tablespoons dried nettle leaf
  • 2 tablespoons dried oatstraw (milky oat tops)
  • 1 tablespoon dried red raspberry leaf
  • 1 tablespoon dried lemon balm
  • 4 cups filtered water
  • 1 teaspoon raw honey (optional)
  • Fresh lemon slices for garnish
  • Ice cubes

How to Make It

  1. Combine nettle, oatstraw, red raspberry leaf, and lemon balm in a quart-sized mason jar.
  2. Pour room-temperature filtered water over the herbs until the jar is full.
  3. Cap tightly and let sit on the counter for 8-12 hours (overnight works perfectly).
  4. Strain through a fine-mesh sieve or cheesecloth, pressing gently to extract all liquid.
  5. Store in the refrigerator for up to 3 days.
  6. Serve over ice with a lemon slice. Add honey if desired, stirring until dissolved.
Hands straining magnesium herbal tea through cheesecloth into glass pitcher with visible pale green liquid and herb sediment
Press the spent herbs gently when you strain. Squeeze them hard and you push the bitter part back into a cup you just spent all night keeping mild.

Herbalist Notes

Nettle leaf and oatstraw are the two herbs at the centre of the nourishing-infusion tradition, and they are the reason this jar exists. Nettle is the deep green, faintly savoury one. Oatstraw, harvested at the milky stage when the seed head releases a white sap if you squeeze it, is sweeter and softer and is the classic herb for people who describe themselves as frayed. Buy oat tops rather than plain straw if you can find them; the difference in the cup is obvious.

Red raspberry leaf is astringent and tea-like, and its job here is flavour and body. Lemon balm is the evening herb of the European garden, used for centuries as the thing you drink when the day will not let go of you. It is also the most fragile herb in this blend. Its whole appeal is a bright, lemony volatile oil, which is exactly what heat destroys, so it is another argument for the cold jar.

Cold-brewing for 8 to 12 hours is not a compromise version of a hot steep. It is a different extraction that favours the mild, sweet, grassy end of these herbs and leaves most of the tannin behind. If you have only ever had hot nettle tea and found it grim, try the jar before you write the plant off.

Make It Your Own

Double the lemon balm if you are drinking this in the evening. The standard ratio here leans on nettle and oatstraw, but 2 tablespoons of lemon balm pushes the whole jar toward that soft citrus-and-garden character. Add a handful of fresh mint leaves during the last hour of steeping for a brighter finish.

For a quick version, steep the herbs in just-boiled water for 15 minutes, strain, and pour over ice. You gain speed and lose the mildness: the flavour comes out noticeably more astringent, and the lemon balm mostly disappears. Sweeten with a teaspoon of elderflower cordial instead of honey for a floral spring note.

Two tall glasses of magnesium herbal iced tea with ice cubes, fresh lemon slices, and mint garnish on outdoor table with spring sunlight and condensation on glasses
Serve this over ice in the afternoon. It is one of the few genuinely refreshing cold drinks that is not built on sugar.

Common Questions

What tea is high in magnesium?

Nettle leaf and oatstraw are the two herbs that come up first whenever herbalists talk about mineral-rich infusions, with red raspberry leaf, alfalfa, and horsetail close behind. I am not going to give you milligram figures for a jar of tea, because the honest position is that nobody measured your jar, your herbs, or your steep. Ordinary black or green tea is not part of this tradition at all. If you actually want to know your magnesium status, that is a blood test rather than a tea recipe.

Can you make a magnesium drink at home?

Yes, and this is the way it has been done for a long time: dried herbs, cold water, a jar, and a night on the counter. Nettle and oatstraw are the foundation and the other two are for flavour and balance. You can make a faster version by steeping the same herbs in hot water for 15 minutes, but you will notice the difference in the cup immediately. Buy organic dried herbs from a supplier that turns over stock quickly, such as Mountain Rose Herbs or Starwest Botanicals, because these particular herbs go dull and hay-like when they sit too long.

What herbs help with magnesium absorption?

This is the kind of question where the internet fills up fast with confident numbers that nobody measured, so here is what I will actually say. Rose hips are the classic vitamin C herb and pair well with a mineral infusion. Ginger is warming and makes the whole thing easier to drink. Adding a little fat to a meal, a few nuts or a slice of avocado, is a decent general habit regardless. Beyond that, if you are trying to correct a deficiency rather than build a nice daily ritual, the useful conversation is with a clinician who can test rather than a page that can only guess.

Is magnesium tea good for sleep?

The herbs in this jar sit squarely in the evening tradition, lemon balm and oatstraw especially, and drinking something unhurried before bed is a genuinely good habit. If you want a warm version instead, our herbal tea recipes cover the hot-steep approach. What I am not going to do is tell you a glass of herbal tea is a sleep treatment, because that is not a claim I can stand behind. Drink 1 to 2 glasses a day if you like it, and notice how you feel over a couple of weeks rather than over one night. If your sleep is genuinely broken, and especially if it has been for months, that is worth taking to a clinician instead of to a bigger jar.

How long does magnesium herbal tea stay fresh?

Strained tea lasts 3 days refrigerated in a sealed glass container. Lemon balm’s volatile oils fade first, and by day four you will notice the flavour has gone flat and faintly metallic. Make a fresh quart every 2 to 3 days and you will always be drinking it at its best. The dry herb blend keeps for 6 to 12 months in an airtight container away from light and heat. If you see mold or the tea smells sour, discard it without thinking twice about the wasted herbs.