Hydroponic Potatoes

  • Nutrient pH 5.8 to 6.2
  • EC 2.0-2.5
  • PPM – 1400-1700

Potato plants can be grown from any potato that has produced eyes. You should actually start from a small slice of a potato known as a slip – which is a quartered potato that has at least one “eye”, it needs an eye to initiate root growth from.

Quick Facts

  1. pH range near 5.8 to 6.2 for optimal results
  2. Temperatures of 65 to 75 degrees Fahrenheit are best
  3. 10-12 hours of light daily optimal – but a minimum of 6 hrs.
  4. Potatoes are prone to rot in excessive humidity.

Starting Hydroponic Potatoes

Planting Potato Slips

Seed potatoes from a nursery or catalog either online or print are generally the best way to go, as supermarket potatoes are treated with a chemical growth inhibitor to prevent sprouting.

Seed Potato from a reputable supplier – for the purpose of growing are generally free of disease. If you buy a potato from the store, be sure to find out if you’re getting a bush type or a vining type.

When planting Potato slips in a hydroponic setup the potato wedge [slip] should be at the very bottom of the bin. As the plant grows -more medium should be added to keep the potatoes covered at all times. Do not allow the potatoes themselves to be exposed to much light as they will produce a bitter, toxic alkaloid [solanine] that imparts a greenish tinge.

Grow Media

See – Growth Mediums

A common problem associated with growing potatoes hydroponically is that the endeavor almost always produces an abundance of relatively small tubers. The potatoes harvested rarely match the size of those grown au naturale, in a natural soil based environment.

As well, the total weight of the harvest – irregardless of individual tuber size is generally less per plant than that grown in soil. Recent improvements in growing methodology, in particular in relation to the media used, show promise of bringing hydroponic potatoes up to par with conventionally cultivated ones.

A blended media, using perlite, vermiculite and peat seems to be the answer. It has produced significantly higher yield, both in total weight and tuber size than potatoes grown in a solitary media [sawdust] . The solitary media does produce more tubers – but small ones, very small. [1]

I like to line the very bottom layer of my grow bags with LECA, it isn’t absolutely necessary but does enhance drainage somewhat. For Potatoes and root crops in general the perlite-vermiculite-peat mix works best. The perlite draws moisture upwards from the base and also maintains ample oxygen within the medium.

The Clay balls are a suggestion only, they are helpful but not absolutely necessary – if you have none available and don’t wish to acquire any you can do without it and skip to the vermiculite-perlite – peat.

Oxygen at the root level is vital for nutrient absorption by the plant. See Hydroponic Nutrients

The vermiculite helps retain moisture.

Tap water is not advisable, but if you are using it anyway allow to stand for at least 24 hours exposed to open air to de-chlorinate. See: Hydroponic Water Quality

Plant the seed potatoes in the perlite, about an inch to an inch and half below the surface. Place them with the cut-side down. Spacing varies a wee bit depending on variety,but basically as a rule of thumb 4 to 6 inches apart will suffice.

Keep the bin covered except to provide water until the potato sprouts begin breaking through the perlite [two weeks roughly].

Light for Hydroponic Potatoes

See – Grow Lights

Once the roots start developing and the plant begins to break the surface – you will need light – it is also at this point in the potatoes development that the emerging foliage will have a hard time getting light where it is growing in the bottom of your bin, while keeping the potatoes themselves from being exposed to light. A reflective material such as mylarmylar for hydroponic use is advisable, foil can also be used but not as efficiently.

Nutrient Solution

Nutrient mixtures vary , you should always consult labels before adding.Generally you would be adding nutrient / fertilizer a minimum of once a week when the sprouts emerge. A teaspoon of 20-20-20 with micronutrients in a gallon of water is best for sprouts.

Once your plants are over a foot high, switch to a high potassium fertilizer which will aid tuber [Potato] growth

Acidity / Alkalinity – pH

In order to enable your potato plants to obtain optimal benefit from the nutrient solution provided, the pH range should be maintained around 6.0 – give or take 2-3 decimals in either direction. Most pH problems are easily avoided by following the label directions of the nutrient that you are using.

If pH does become an issue –

To lower a high pH small amounts of distilled white vinegar will work, some people also use aspirin, although I’ve never tried it myself.

A low pH can be corrected {increased} by adding sodium hydroxide or potassium hydroxide to the water. Small amounts of one or the other should be used. Never touch hydroxides with wet hands. Handle them as little as possible and when you do, use sturdy water resistant gloves.

IF possible, test any pH adjustments on a single plant before you continue to make adjustments to your entire nutrient solution. See: pH in Hydroponics

Potato plants perform best in warm weather. Temperatures of 65 – 75 degrees Fahrenheit are best but naturally this will vary from cultivar to cultivar.

Related: Spinach Grown Hydroponically