What it involves week to week

Planting day is the busy one: you sprout seeds in small starter cubes, mix fertilizer into a container of water, adjust its acidity and set the seedlings so their roots reach the solution. After that the routine is short. Every few days you look at the water level, test the pH, and check the leaves for pale or scorched patches. Every two to three weeks a system with a pump gets drained and refilled with fresh solution. Indoors the light usually comes from an LED on a timer. A few jars or a countertop garden fit on a shelf or a counter near an outlet. Towers and tents need floor space and a surface that can take a spill.

A hand lifting a parsley plant in a black net cup out of a growing channel, its bare white roots dripping — A net cup lifted out, bare roots dripping

Which kind should you start on?

Kratky methodThe passive way. A plant sits in a net cup above a container of nutrient solution, and as it drinks the level down, the roots left in the air gap take in oxygen. No pump, no electricity for the water and almost no upkeep. It is the cheapest way in and the best one for learning what the numbers mean. Best for lettuce and herbs, one plant per jar.

Start here

Start two lettuce seeds in a starter cube this week. When roots show at the bottom, set the cube in a net cup on a jar of mixed nutrient solution and cover the glass so light cannot reach the water.

UF/IFAS passive lettuce guide

Countertop gardensA plug-in appliance with a water tank, a quiet pump and an LED light on an arm, sized for a kitchen counter. It tells you when to add water and plant food. Pick it if you want fresh herbs with the least setup and are fine with 6 to 12 small plants.

Start here

Set the garden where you will see it every day, fill it to the line, plant lettuce and basil in the baskets it came with and add plant food when the reminder light comes on.

AeroponicsRoots hang in air inside a column and are wetted by solution that a pump sprays or trickles over them. Home versions are vertical towers that grow 15 to 30 plants on about two square feet of floor. Pick it when you want real salad quantities from a small footprint. The pump has to keep running, so a failure dries the roots out within hours.

Start here

Find a spot near an outlet with a hard, level floor, assemble the tower and run it with plain water for an hour to check for leaks before you add nutrients and seedlings.

Grow tentsA fabric enclosure with a reflective lining that holds a strong light, a fan and a bucket system. It turns a basement or spare-room corner into a small growing room with its own climate. Pick it when you want a steady supply of greens through winter or have no bright spot in the house.

Start here

Measure the corner where the tent will stand, including the ceiling height, and put the tent up empty. Hang the light, run it on the timer for a day and check the temperature inside before you plant anything.

Open a card for the first thing to do. Its button puts that way of growing in the shelf list on top of the base kit, and takes the other three out.

The passive method, step by step

UF/IFAS: "Set It and Forget It" Hydroponic Lettuce Free step-by-step for the passive method with fill levels, fertilizer rates and target readings

Hands setting sprouted starter cubes into the planting holes of a white tray

Your first planting, start to finish

Sprout, mix, test, plant

What you can grow in your first month

Rooted seedlings

Lettuce and basil sprout in starter cubes within a week, and white roots poke through the bottom a week or so later.

A basil cutting with roots

A stem from a grocery-store bunch grows roots in plain water in about two weeks and then moves into a net cup.

A half-grown lettuce

By week four the plant is about as wide as your hand, and you can pick a few outer leaves while the head finishes.

A second planting

Seeds started two weeks after the first, so the harvests arrive in turn instead of all at once.

The numbers you manage

4.05.06.07.08.0

Acidity (pH), 5.5 to 6.5

Outside this range plants cannot take up some nutrients even when plenty is in the water. Tap water usually starts higher, and nutrients pull it down, so always test after mixing.

Nutrient strength

Measured as EC, or as TDS in parts per million. Lettuce and herbs like a mild solution, around 560 to 840 ppm. Fruiting plants want more. A reading that climbs as the water level drops means the plants are drinking faster than they eat, so top up with plain water.

Water temperature, 65 to 75°F

Warm water holds less oxygen and invites root rot. Keep containers out of direct sun and off heat sources.

Light hours

12 to 16 a day for leafy crops. The same hours every day matter more than extra hours on some days.

Root color

Healthy roots are white to cream and smell like nothing. Brown, slimy roots with a swampy smell mean rot. Change the solution and cool it down.

What trips beginners up

Starting with tomatoes or peppers

Fruiting plants need stronger light, more nutrients, support and three months or more. Grow two rounds of lettuce and herbs first.

Garden fertilizer instead of hydroponic nutrients

Fertilizers made for soil leave out calcium, magnesium and trace elements that soil normally supplies. In plain water the plants run short within weeks.

Light reaching the water

Green algae grows wherever light meets nutrient solution. Use opaque containers, or wrap clear jars in paper, foil or a sock.

Drowned roots

A passive jar refilled to the brim suffocates the roots that had adapted to air. Refill halfway at most.

Tall, thin, pale seedlings

The light is too weak or too far away. A windowsill in winter is rarely enough for lettuce.

Chasing the pH

Adding big doses of adjuster swings the reading back and forth. Add a little, stir, wait a few minutes, retest.

Expecting it to be cheaper than the store

A few jars of lettuce will not beat grocery prices once electricity and nutrients are counted. The payoff is freshness, variety and the growing itself.

A seedling with its first true leaves growing from a starter plug in a white tower port — A seedling in its starter plug

Water, electricity and clean produce

Keep plugs above the water

Mount power strips and timers higher than the reservoir, and let each cord dip below its outlet before rising to it so drips fall off instead of running in. Use an outlet with ground-fault protection (the kind with test and reset buttons).

Treat pH adjusters as strong chemicals

The adjuster sold as pH down is an acid and the one sold as pH up is a base. Add them to water a few drops at a time, never mix the two concentrates together, rinse any splash off skin right away and store them away from children and pets.

Mind the weight

Water weighs about 8 pounds a gallon, so a full 5-gallon bucket is over 40 pounds. Set systems on the floor or on shelving rated for the load.

Wash your hands and the harvest

Handle plants with clean hands, rinse leaves in drinking water before eating and sanitize the system between crops. Do not use collected rainwater for salad greens.

Where to learn more

University extension guides

Free, tested and written for home growers. Start with the two linked on this page, then search your own state extension for hydroponics.

Online grower communities

The Hydroponics forum on Reddit is where people post photos of leaf problems and get a diagnosis within hours. Include your pH, your nutrient reading and a photo of the roots when you ask.

The nutrient label

Every maker publishes a feeding chart for its product. Follow the chart for your nutrients over generic advice, starting at the low end.

Looking down the side of a white growing tower with young lettuce plants in its ports — Young lettuce in the ports of a tower

Free guides and a place to ask

How the shopping list is built

The base kit is what every method uses: nutrients, a way to test and adjust pH, seeds and starter cubes, plus a meter for nutrient strength that is worth having once you mix your own solution. On top of that you add the gear for one way of growing. The Kratky method costs the least because the containers are jars. A countertop garden or an aeroponic tower is one purchase that includes its own pump, and usually its own light. A grow tent is the largest step, since the tent, the light, the bucket system, the timer and the fan are bought separately. Most of the money is spent once. The repeat costs are nutrients, seeds and starter cubes, which come to a few dollars a month for a shelf of greens. The low end of the cost estimate is the base kit plus the jars, net cups, pebbles and a small light. The high end is the base kit, the meter and a full tent setup at mid-range prices.

A hand reaching toward a bok choy plant growing from the side of a white tower

Stock the grow shelf

A base kit, plus the gear for one way of growing

The first five lines are the base kit and start in the shelf list. Everything after them belongs to one way of growing and stays out of the total until you switch that way on, here or in the list. Clicking a card selects it, and clicking the selected card again takes that line out.

Hydroponic nutrients for leafy greens and herbs

Essential · Consumables

Water has no food in it, so everything the plant eats comes from this. Hydroponic formulas include the calcium, magnesium and trace elements that soil fertilizers leave out.

budget

General Hydroponics MaxiGro Plant Food for Vigorous Growth, 2.2 lbs.

4.6(4180)

$16.99

Hydroponics

What it involves week to week

Which kind should you start on?

Your first planting, start to finish

The numbers you manage

What trips beginners up

Water, electricity and clean produce

Where to learn more

How the shopping list is built

Stock the grow shelf

Hydroponic nutrients for leafy greens and herbs

Hydroponic pH control kit (pH up, pH down and a test liquid)

Lettuce and herb seeds

Rockwool starter cubes

Digital TDS and EC meter

Wide-mouth half-gallon glass jars

3-inch net cups for wide-mouth jars

Expanded clay pebbles

Small LED grow light with timer

Countertop hydroponic garden

Vertical aeroponic tower garden

2 by 2 foot grow tent

Full-spectrum LED grow light panel

Deep water culture bucket system with air pump

Outlet timer

Clip-on fan