All over the world, in homes and offices, on porch pots or on windowsills, in grow rooms or city rooftops, people are growing plants using water, not soil. If you’re still buying herbs, plants, or vegetables, here’s what you can grow without soil.
Herbs such as basil, sage as well as fruits, flowers, houseplants, and garden plants can be grown without any soil by using different water-based systems such as hydroponics, aquaponics, aeroponics, or fogponics. However, edible herbs and vegetables cannot grow exclusively using water, nutrients need to provide in order to sustain growth.
Indoor gardeners who grow herbs in water enjoy the benefits of going soilless: no weeds, no dirt, no pests, less damage, better harvests, and year-round crops that are easy to move around.
Let’s explore some forgotten plants and popular herbs that you can grow in water.
Leaves can absorb oxygen from the air, and roots absorb oxygen from water in the soil. Plants are naturally programmed to find, release, and absorb oxygen in water by using three (3) processes: cation exchange, osmosis, and diffusion.
Great question! We know that fish breathe underwater because they have gills. But how do plants do it? How do they absorb oxygen – and even nutrients – from water?
Here’s the answer: The root hairs absorb nutrients via osmosis as well as via diffusion. Let me explain.
Osmosis: First of all, osmosis is when the roots “grab” or absorb nutrients and oxygen around it in water.
Diffusion: On the other hand, diffusion is when the same nutrients and oxygen spreads from the roots towards all parts of the plant where these are needed.
Plants also absorb oxygen from the air, from soil, and from water. Here’s how they do that:
From the air: Plants absorb oxygen from air through invisible pores on leaves (stomata).
From the soil: When the main root digs downwards into the soil, it also spreads side (or lateral) roots towards where the plant senses the presence of water. The rootlets automatically branch out and grow towards soil moisture.
Roots absorb oxygen from small pockets of air in the soil. This is why overwatering removes those air pockets and can drown a plant to death.
From the water: On the other hand, when you root a plant in water, there’s another story. The roots release nutrients minerals in soil particles (cation exchange), absorb and distribute them throughout the plant (diffusion).
In this process,root hairs pump positive hydrogen ions (H+) to the soil to release nutrients such as Calcium (Ca) and Magnesium (Mg) from negative soil particles. These nutrients are then released in the water, which the root hairs can absorb into the plant.
How does this matter to indoor herb growers? Here’s how:
Culinary herbs grown indoors have less aromatic oils. Flavors and fragrances won’t be as rich. This is because most herbs are land-based (non-aquatic) plants. In water, they won’t grow like if they were grown in soil.
For instance, growing on soil means that roots are thicker to anchor the plant securely. In comparison, water roots are very fine to absorb oxygen and nutrients. These roots are so thin and fragile that they can be easily attacked by bacteria or pathogens. (Hint: keep the water clean at all times!)
In addition, you can’t just drop a basil cutting in a glass of water and expect it to become a full plant. Indeed, after a while, without any extra source of nutrients (the water has barely any) the plant will wilt and die.
This, however, shouldn’t stop you from growing herbs in a glass of water – as many others do. The advantages of having your favorite food ingredients, condiments, and flavorings on hand, year-round, and savings in terms of grocery bills and convenience are simply irresistible.
Here’s a choice of herbs that you can propagate in water.
PRO TIP: When cuttings of soft-stemmed herbs (e.g., oregano, stevia, mint) are placed in water, they generate special roots that can absorb nutrients from water instead of the soil.
HINT: Dissolve an aspirin tablet in the water for better rooting. Add pebbles to enrich the water with mineral nutrients that help the plant thrive to full maturity.
The best plants to grow in water are aquatic plants such as arrowhead, brooklime, bur reed and more. Although widely used in native cuisine in ancient times, they’re rare among today’s herb growers.
Water gardening started in ancient history after people gathering edible plants in ponds, lakes, and rivers decided to grow them closer to the kitchen. Today, traditional chefs around the world still use them, sourced from farmers around the world.
However, these plants are largely forgotten in modern cuisine. Even so, you can find them around, growing in garden ponds, lakesides, marshes, rice paddies, wetlands, and in other bodies of water.
For instance, if you have lotus (Nelumbo nucifera) in your garden pond, you might be surprised to know that it’s been used in ancient dishes of the Chinese, Egyptians, and North American Indians.
And that’s not all. Here are other examples:
Arrowhead (Saggitaria latifolia) tubers have a delicious, nutty taste;
Brooklime (Veronica beccabunga) is widely used in salads in Northern Europe;
Bur reed (Sparganium erectum) yields edible oil, while its leaves, stems, tender tubers, and root stalks are great when steamed, boiled, stir-fried, or in raw salads;
Cattails (Typha latifolia) white stems inside its lower leaves can be steamed or boiled like celery and eaten like the ear of corn. The yellow pollen can add fats, proteins, and vitamins to pancakes, muffins, or bread. The root can be used as a starchy vegetable.
Chocolate mint (Mentha x piperita cv.) is great for teas, as a palate cleanser, and to repel rodents and insects;
Flowering rush (Butomus umbellatus) has edible starchy bulbs to thicken soups, can be added to flour in making bread, and can be used as tallow for candles;
Galingale (Cyperus longus and C. esculentens) roots were used to spice sweets, soups, and pies in the Middle Ages;
Kangkong spinach (Ipomoea aquatica) makes tasty greens in soups and garnishes;
Lebanese cress (Apium nodiflorum) gives a celery-carrot taste to coleslaw, salads, and sandwiches;
Pondweed (Potamogeton natans) root-stalks are nutritious and leaves tasty;
Vietnamese mint (Persicaria odorata) is used in refreshing drinks and dishes;
Watercress (Rorippa nasturtium aquaticum) is a well-known vegetable used in soups and salads
Water mint (Mentha aquatica) makes the best mint julep, bar none.
Most indoor herb growers are not familiar with many of the plants that I’ve included in this list. If you try to grow and use them in your dishes, you’ll stand out for sure! And I mean not only as a foodie but also as an herb growing enthusiast.
It is not possible to grow plants in water only with just the provision of water. If a cut is placed in water it might grow and thrive even for weeks before wilting and dying for the lack of basic nutrients and minerals present only in a minimum amount (or absent) in tap water.
Here are four (4) ways that indoor gardeners, farmers, and even large-scale crop growers use:
1. Hydroponics: This word means using only water to grow plants. It’s as simple as putting a seed or stem in a glass or dish of water, or as extensive as an entire greenhouse or farm with interconnected water pipes.
2. Aquaponics: This is like hydroponics, except that the plants grow above a tank of fish (or shrimps, mussels, and so on) that input nutrients into the water. This is the water that’s pumped to the plants. The plants input oxygen into the water that goes down to the fish tank.
3. Aeroponics: This means spraying water into the air so that the roots and leaves of plants absorb the moisture.
4. Fogponics: This is the same as aeroponics, except that high pressure is used to spray water in the form of mist or fog. You can use a pressure spray pump or a jet fogger.
FACTOID: Soil-based plants that are grown in water can produce more food for us because they don’t need to use so much energy to develop land-type roots.
Many herbs are easy to grow with only sunlight, clean water and nutrients provided for instance with mineral-based fertilizer or rock dust for nutrition. Higher chances of success are given by hydroponic systems.
Whether you’re growing plants to decorate indoors, to grow organic food, or to beautify a garden, here’s a list of herbs and fruits that you can grow in water.
Basil – Place basil cuttings in glass jars with water. Provide bright sunlight (indirect or partially shaded at first) and change the water every couple of days.
Celery – Place healthy celery cuttings in water. Expose to full sunshine. Change the water every couple of days.
Chives or garlic sprout: Place an unpeeled garlic clove and in a glass or dish with a little water (don’t submerge the entire clove).
Coriander – Press gently until seeds split into halves. Sprinkle the seeds in a net basket. Fill a container with water. Place the net basket on the water. Cover with cloth or paper. Expose to bright but indirect sunlight. Change the water twice a month.
Fennel – Use the last two inches of the plant with the roots intact. Put in a small glass container with water. Top up or refresh the water from time to time.
FACTOID: The baby leaves of coriander are called cilantro.
Garlic – Submerge a clove (with some green sprouts) in a glass of water. When the sprouts are about four inches high, you can cut off about a third of the shoot for use.
Ginger – First, let the ginger take root in compost. When leaves and stems sprout, move the ginger root to a container with water.
Lavender – Use a cutting with up to 5 lower sets of leaves (not at the tops of stems). Put some pebbles or rocks in the bottom of the container to keep the cutting upright as well as to provide mineral nutrition to the plant.
Leeks: Place the white lower parts of the stalk (at least 3 inches long) in 2 inches of water, expose to sunlight, and replace the water every 3 days. The green part will regrow in about 3 days.
Lemon balm: Cut a stem from a mature plant, position the cutting upright in the water, and wait until new roots grow.
PRO TIP: Plain water doesn’t have the nutrients that plants need to thrive.
Lemongrass: Trim away all brown leaves. Place the bottom two or three inches of stalks in an inch of water. Expose to sunlight when the green parts regrow. Replace cloudy water.
Marjoram – Submerge the end parts of cuttings in a glass of water. Put the glass on a windowsill for sunshine. Change the water regularly. Some rock dust such as can add minerals to the water, which are essential for plant growth and development.
Mint – Place healthy cuttings in water with a little water. Change the water every no in then to prevent stinking. Expose to partial sunshine for better photosynthesis.
Onion – Place an onion root end down in just enough water to cover the roots. Every other day, change the water. Position the plant near a well-lit window.
Oregano – Place cuttings upright in a container with about 2 inches of water. Expose to partial or dappled sunlight. Change the water every 4 days or when the water becomes cloudy.
PRO TIP: Carbon dioxide bubbles in carbonated water makes plants grow faster.
Parsley – Use cuttings about 3 inches long. Remove all lower leaves. Let the cuttings stand in a container of water (water shouldn’t touch the leaves). Replace the water every 3 days or so.
Pepper – Use a cutting from the lower half of a pepper plant. Position the cutting upright in a glass with water. In cold months, cover with a plastic wrap and expose to indirect sunlight.
Rosemary – Use a cutting about 8 inches long. Remove the outer skin on the lower half of the cutting. Place in a container and add enough water to cover the stripped stalks. Place in a sunny location.
Sage: Place cuttings in a little water with the cut end down. To prevent mildew, place the container where there is good ventilation and sunshine. Replace the water every other day or so.
Salvia: To propagate, put cuttings in 8 cm. of water. Use a glass container to see roots growing in 3 weeks or less.
Shallots (or spring onions): Use stems with long roots. Cut the green tops and place them upright in a glass container. Add water to cover at least half of the white stem. Keep the plant where it can get sunlight. Replace the water every 3 days.
Stevia: Place several cuttings in a container. Add fresh water (stem level only) until roots grow in 4 weeks or longer.
Thyme: Cut at the node (where leaves join the stem of the plant) of some healthy, bright green stems. Remove the leaves on the lower portion of the stems. Place them in a container of water immediately.
PRO TIP: When you grow herbs in water only, they can become thin, spindly, and show smaller leaves. You should rotate pots often so that all parts get sunlight for uniform growth. Try and add water-soluble fertilizer at least 2x a month. Also, add pebbles or rock powder to infuse minerals into the water.
There are so many more herbs that you can grow in water. And, if you haven’t noticed, whichever herb you choose to propagate without soil, the 3-step process is practically the same: cut, add water, and expose to gentle sunshine.
Growing cuttings in water is a cheap and easy shortcut, simply because seeds take longer from germination to maturity.
Here are five general steps to follow when growing plant cuttings in water.
- Choose: Select a stem from 4 to 6 inches long in a mature, healthy plant.
- Cut: Cut the selected stem part below a leaf node.
- Clean: Remove dirt, debris, and the lower leaves on the stem (just leave 2 to 3 couple of leaves at the top).
- Immerse: Use clean water in a glass or transparent container to enjoy the view of the roots growing.
- Expose: Provide partial or shaded sunlight for 2 weeks or until roots emerge.
You can enjoy soilless gardening, whether you use a glass jar by your window to grow a few herbs or you use a sophisticated pipe-and-pump system to grow crops for profit.
Whatever your choice is, these five (5) general tips can help you achieve the best results:
Know your plants: Know what plants can be regrown in water from scraps, grown totally in water, or rooted in water for transplant.
Know the parts to use: Know the parts of the plant that can be used for this purpose.
Use good stocks: Choose healthy plants. Don’t use plants or seeds that are genetically modified or treated with insecticides, preservatives, or growth retardants. Use chilled runners instead of uprooting from the soil, which may have pathogens or diseases.
Provide plant needs: Apply the correct growing conditions such as a little or a lot of water, partial or full sunshine, changing the water, or adding liquid nutrients.
Set proper expectations: You won’t be disappointed if you know which plants are easy and which ones are challenging to grow in water; which plants regrow partially or completely; and which plants regrow like the parent plant and those that regrow differently.
People who grow plants in water indoors enjoy the many benefits of not using soil. No dirt means no pathogens or infections. Plants are more protected indoors and can be harvested all year round.
No herbicides or pesticides: Plants are protected from pests, birds, and other animals. This means bigger, better fruits and leaves. In addition, there’s no need to deal with dirt, weeds.
Easy watering and mobility: There’s no danger of overwatering or underwatering that can kill plants. Also, and plants can be rearranged to maximise space or protect them from extreme weather
Choice of methods: You can use hydroponics, aquaponics, aeroponics, or fogponics depending on your needs and budget. It’s as simple as sticking a stem or seed in a little water or using a complex water piping or spraying system for a large crop.
Choice of plants: Choose plants that can be grown without dirt or soil, only water and light. At least 23 herbs and 4 fruits are described in this article.
Have you tried growing plants in water only? If so, I’d really love to hear from you!
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