Hherb garden

Backyard hydroponic culinary herb garden.



As dawn breaks, young sprigs of peppermint are selected for morning tea. At lunch, basil is selected for a pesto sauce. During the day, fresh rosemary is added to bread, and a teaspoon of tarragon is harvested for a supper dish. In the evening, sage leaves are brewed for a bedtime tea to aid in a good night’s sleep.

In today’s world of outdoor kitchens, a hydroponic herb garden can be easily added to the space, bringing aromas, flavours and a welcoming ambience to the space. Most culinary herbs are thought to have medicinal properties as well. A few studies have shown that the active phytochemicals in hydroponic herbs are as good or better than soil grown. Hydroponic herbs can be grown with organic or inorganic nutrients.

Quality of life can be improved with fresh picked herbs for teas and cooking. No chef anywhere in the world has access to higher quality herbs picked fresh as needed, growing within arm’s reach.


In Fair Play, Missouri, The Institute of Simplified Hydroponics has designed and built a hydroponic culinary herb garden. This garden is placed in a corner of an outdoor kitchen area is a huge success in increasing the comfort, aroma and flavour of food and beverages.

The first herb grown in the outdoor kitchen was a single 18”diameter container of peppermint. The pot is a commercially available pot with a 1” diameter hole in the bottom for drainage. For hydroponics, a circle of plastic screen was placed in the bottom of the pot, to retain substrate. The pot was filled with perlite, and a peppermint planted in the center of the pot.

The plant is watered once a day with hydroponic nutrient water sprinkled from watering can. Several commercially available hydroponic nutrients have been used with success. The plant uses about one quart of nutrient water a day. The two-year-old plant has produced about six fresh new peppermint sprigs a day, enough for two cups of tea. The single peppermint plant has so far supplied mint for over 600 cups of tea and may continue for years in the future.

Probably any culinary herb can be grown in a similar manner.


Different herbs are popular in different countries and different cuisines. There are also some universal favourites that we include in our garden. Herbs are harvested from fresh new growth and any flowers are pinched back to inhibit going to seed.

Mint: we have two 18” diameter containers, one with peppermint and the other spearmint. Both are very productive providing for four cups of tea a day. The mint tea can be drunk hot or cold. Mint is thought to have antiviral and antibiotic components that help fight colds and flu.

Genovese basil: a variety of sweet basil used to make Italian Pesto for pasta. Basil also makes a tea that is slightly lemon flavoured, a favorite with children. We have four containers from 15” to 18” diameters. This produces enough basil to make a pesto every three days.

Sage: used as a seasoning for dressing and also a favorite tea in many cultures. We have two 12” square pots of sage that will eventually grow to be about two feet tall. This allows for two to four cups of sage tea a day.

Rosemary: a favourite herb used in breads and dishes. Skewer rosemary produces natural skewers for barbeque. Also used as a tea. We have three 12” pots in the garden, enough for about two sprigs a day.

Chives: used as a substitute for onion in some dishes, added as a garnish for salads. We have two 12” diameter containers of chives growing about a tablespoon a day.

Fennel: used as leaves and the root bulb. A flavouring for a tea, and used in dishes. Fennel tea is considered medicinal to treat colds, repertory issues and Alzheimer’s. The bulb end is used as a vegetable. The bulb ends are harvested every 60 days and new plants are planted. We have one 15” diameter pot in the garden allowing for about a tablespoon a day.

Parsley: used in dishes, as garnish and as a tea. Considered a medicinal tea to promote body cleansing. We have two pots growing about a tablespoon a day.

Cilantro: used in Mexican dishes such as salsa. We have two 18” diameter pots growing about ½ cup a day.

Oregano: we use Italian and Mexican oreganos. Used in pizza, Italian tomato sauces and as a herbal tea. We have two small pots of 9” diameter allowing for about a teaspoon a day.

Stevia: used as a natural sweetener. Sprigs can be added to teas instead of sugar. We have two 12” pot growing about a teaspoon a day.

Tarragon: used in soups and stews. Makes a great beverage sold as a commercial drink in many countries. We have one 12” pot growing about one tablespoon a week.

Dill: use seeds and fronds as a flavouring for pickles, on toast, in breads. Makes a great tea with calming properties. We have one 12” pot growing about a teaspoon a day.


Several of the herbs can be used to brew in teas, served hot or cold. By brewing teas, the water is brought to a boiling point, likely to kill most bacterial disease and have added minerals from the herbs. The basic recipe is three 3” sprigs of herb, with honey, lemon or salvia to taste.

A 12-ounce can of Coca Cola has 9.33 teaspoons of sugar. If fresh herb teas are replacing sugar soft drinks, they can be help in improving daily diet.


The Genovese basil in the herb garden is used to make pesto. This requires a cup of fresh basil, so it will use much of the growth from an 18” planter, each week. It does not require cooking, so it reduces need for energy used in a cooked sauce.


  • 1 cup basil leaves (125 grams)
  • 1 garlic clove
  • 1 tablespoon pine nuts
  • 1 ounce parmesan cheese grated
  • ¼ cup olive oil

The ingredients are placed in a food processor or a mortar and pestle and blended together. Pesto in blended into cooked pasta or used in meat dishes and stews. It offers outstanding flavour that is likely to be a family favorite. The cheese can be replaced by a grain product and the pine nuts with peanut.

Salsa Cruda

  • 6-8 vine-ripened tomatoes
  • 1/2medium yellow onion
  • 2-3 jalapeno chilies
  • 1/2 cup chopped cilantro

Chop up ingredients and serve in bowl with chips, or on food. Two 12” containers of cilantro will supply enough to make this recipe every day.


Our herb garden is hand watered with a watering can of hydroponic nutrient. This helps establish the herbs, as over-pouring with nutrient water allows plant to obtain some nutrient from their leaves as well as the roots. This action alone should see a 40 per cent increase in growth rate as opposed to watering the roots only.

To hand water a garden of about 20 plants takes about four gallons of nutrient water a day, and about five minutes to mix the water and hand water the garden. With a simple system such as this, there are no parts to buy, and no systems to fail. So this is the most foolproof method of watering the plants.

However, the garden herbs should be hand watered once a day and there are times when this is difficult. Illnesses and family emergencies will happen. Family vacations require being gone a week or more. Unless there is a very kind neighbour or friend nearby, the garden can be automated to give a daily feeding of nutrient water.


There are several hydroponic systems on the market that can be used to create an automatic watering system for the garden. Some of these require electricity and as least one, the AutoPot system, can be operated without any external source of energy. These systems are an excellent alternative to hand watering to keep your garden growing while you travel.

Drip irrigation systems

If you have a pressurised water system, such as a city water supply piped into your home, you can set up a drip irrigation system. Most of these systems require a pressure of 45 psi and so they will not work in areas where there is no pressurised system.

These drip systems are offered by a few different companies and can be set up to attach to an outside hose. The systems create a watering line that can be used to ensure water to the plants.

These drip irrigation systems are not designed to be used in hydroponics, and use small emitters that can easily clog when delivering nutrient water.

A second issue is a possible failure of the system that allows water to flow freely to the ground. Left unattended, this can lead to flooding of your property and costing money for a huge water bill. This happened to us at the Institute, and left us with an unexpected US$300 water bill.

Gravity-fed drip irrigation

Where there is no pressurised water, a drip irrigation system can be set up using gravity as the energy source. In this case a water container is placed at least three feet above the ground, and the drip system is used for plants below. At three feet high, the gravity-fed system has a zero to two psi water pressure.

The water supply

For our garden we use a 50-gallon water barrel on the ground and a 30-gallon barrel placed above that for the hydroponic nutrient. Both barrels are placed in a shade area to reduce the heat buildup from the sun, and both are tied to a tree to keep them from toppling on anyone.

The hydroponic barrels are food grade recycled barrel purchased for US$10 each. A plastic spigot with on and off shut off is placed on the barrel by drilling a hole and attaching to the barrel. When attaching the spigot, Teflon tape is used to make a tight seal.

Drip system

We use a system common to the drip industry of a backflow valve (to prevent liquid from siphoning back into a tank, a 200 mm filter (to collect large particles from the system) and a device to change from hose fittings to a ½ size polyethylene tubing.


A timer can be used to set a watering time for each day. Most drip irrigation timers need some water pressure to work, so it is necessary to purchase a zero pressure timer for a gravity fed system. Unfortunately, there are just a few zero pressure timers on the market and most have poor reviews on Amazon. We are using a Toro Zero gravity timer and it appears to be working but some Amazon reviews claim this timer might fail in a few months.

Tubing line

For gravity fed, we use a ½” diameter tubing from the timer, and use only one line through the garden. If the line is split into two lines, one may be slightly lower than the other and fail to get much water. That one line curls through the pots and ends on the ground. About every 12” the line is punched and a ¼” tubing fitting placed in the ½” line. Tubing of ¼” is cut to length and placed in each pot with a spike to hold the tubing. In a pressurised system, emitters would now be placed at the end of the ¼” tubing.


In our system, the pipe is placed near the center of the pot and no emitter is added. Nutrient water is allowed to flow freely from the ¼ inch tubing. This is to reduce cost, and to better ensure each plant gets its daily water.

Generally, the larger 18” pots require about a quart (one litre) of water a day and the smaller about ¼ of that. So lines are placed to the larger pots first. A line such as this usually works for about 10 to 20 pots before the water pressure is gone.

In debugging the system, you run the timer and see how the plants are getting their water. In a certain about of time, the plants will receive what they need. The timer is set for that time, usually about 10 or 20 minutes.

Hydroponic added to the barrel

When the system is set up the top barrel is filled with water and hydroponic nutrient is added to the water according to the instructions of the manufacturer. When the barrel is emptied, more water and nutrient are added.

Fresh water flush

No matter what watering system is used, the herb garden is watered with fresh water once a week to flush the system of excess minerals. This is done with the fresh water stored in the bottom barrel. Water is delivered through a hose and or a watering can to the garden.

Pop bottle-fed systems

There are some designs of irrigation systems that use repurposed pop bottles placed in the plant containers to deliver small amounts of water. A few of these use bottles just cut off at the top and nutrient water would be poured into the bottles as needed. A couple of holes are drilled on the bottle or in the cap to drip water onto the plant roots.

One issue for this system is the open container of water is an invitation for mosquitoes and needs to be protected. If using a method such as this, the top of the open bottle should be covered with an insect screen to prevent mosquitoes from entering.

This type of watering system can be useful to keep plants alive for a few days or as long as the water holds out. However, our 18” pots that require a litre of water a day only have a two-day supply of water in a two-litre bottle. For a 10-day stretch they would need a 10-litre bottle and that is getting very large.


If you are new to hydroponics, a culinary herb garden is a great place to start. Herbs, once established tend to grow well and are very welcome in the daily diet. If herbal teas are used to replace soft drinks there should be a reduction in daily sugar. If herbs are used in cooking, they can replace most of the salt in the diet.

The real reward comes from serving a pesto on spaghetti and having guests tell you are a great cook. Your secret weapon was the outrageously great flavour and aroma of the hydroponic basil. b

It is easy to start. The daily rewards are worth it.

For more information and kits to support this garden visit our website at

About the author

Peggy Bradley is the CEO of the Institute of Simplified Hydroponics, a non-profit organisation based in Fair Play, Missouri, USA. She has a Masters in Civil Engineering and has been active in hydroponics for over 50 years. Her work has been primarily in the field of Simplified Hydroponics and has visited over 16 countries working to establish the technology. Contact:, see website for more info at

(Full story and images in Practical Hydroponics & Greenhouses, August 2017 / Issue 182)  Ω