Rocket Salad

Quick growing conditions

How to Grow Rocket Salad Hydroponically at Home

Rocket salad, also called arugula or rucola, is a fast-growing leafy vegetable with a peppery flavour. Hydroponic growing lets you harvest fresh leaves at home without soil.

This guide focuses on cultivated rocket, Eruca sativa, also classified as Eruca vesicaria subsp. sativa.

Choosing Your Rocket

Cultivated rocket is an annual with relatively broad leaves and a short growing cycle. Choose a variety described as slow to bolt if you want a longer leaf-harvesting period.

Wild rocket, Diplotaxis tenuifolia, is a different species with narrower, deeply divided leaves and a perennial growth habit. Its growth cycle differs, so the nutrient profile below should not automatically be treated as an optimum for wild rocket.

Main Growing Conditions

These temperature and lighting settings are practical home-growing starting points, not strict limits or settings tested together in the nutrient study. Lux readings depend on the lamp spectrum.

Rocket grows well in cool conditions. Warmer temperatures can still support growth, but heat increases the risk of early flowering. Above approximately 29°C, protecting plants from overheating becomes particularly important.

Long days can also encourage bolting. Extending the lighting period is therefore not always useful when the aim is continued leaf production.

Choosing a Hydroponic System

NFT is suitable for hydroponic rocket and was used in the nutrient study below. Keep the solution circulating reliably and prevent roots from obstructing the channels.

An aerated deep-water system is another option for home growing. Keep the crown above the solution and ensure the roots receive oxygen.

Cover the reservoir to reduce algae and evaporation.

Recommended Nutrient Profile

The following profile reproduces treatment NS2 from Cavarianni et al. (2008), an NFT study comparing nutrient solutions with different nitrogen concentrations.

All values are in mg/L of the finished nutrient solution. N is total elemental nitrogen. P and K are elemental phosphorus and potassium.

The study supplied approximately 10% of total N as ammonium nitrogen. Its iron source was EDDHMA-chelated iron.

This is one published treatment, not the study’s claimed universal optimum. Other treatments differed in nitrogen, sulfur and chloride concentrations. Do not change nitrogen alone and assume that you have reproduced another treatment.

Recipe source: Cavarianni et al. (2008), “Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution.” See Table 1 and the Materials and Methods section.

Use this profile as a starting point and modify it according to your growing conditions. Include nutrients already present in your water when calculating fertilizer quantities.

Measure EC after mixing. The published EC does not guarantee the same reading with different water or fertilizer salts.

Use our NPK Calculator to formulate your nutrient solution.

Regular Care and Preventing Bolting

Check water level, pH, EC and circulation regularly. Provide gentle airflow around the leaves and remove damaged foliage.

Harvest regularly and avoid overheating. If a flower stalk develops, removing it may briefly extend harvesting, but it does not permanently reverse the plant’s transition to flowering.

Cultivated rocket is an annual. For a continuous supply, grow successive batches rather than expecting one plant to produce tender leaves indefinitely.

Pollination is unnecessary when growing rocket for leaves.

When and How to Harvest

Baby leaves can be ready approximately four weeks from seed. Larger leaves commonly take around six to seven weeks. Variety, temperature and lighting can change these timings.

Begin harvesting when leaves reach a useful size, approximately 5–8 cm for small salad leaves.

Pick the outer leaves and preserve the central growing point so the plant can continue producing foliage. Avoid removing most of the leaves at once.

Young leaves generally have a milder flavour. Older leaves and plants approaching flowering can become stronger or bitter.

Common Problems, Pests, and Diseases

• Early flowering: Review temperature and lighting duration. Choose a slow-bolting variety and harvest young leaves.
• Aphids: Inspect growing tips and leaf undersides. Isolate affected plants and remove pests early.
• Flea beetles and caterpillars: Check leaves for small holes and feeding damage, especially if plants or equipment have been outdoors.
• Leaf spots or powdery mildew: Improve airflow, avoid prolonged leaf wetness and remove affected foliage. Symptoms require proper identification before treatment.
• Wilting or deteriorating roots: Check circulation, aeration, temperature and cleanliness before increasing fertilizer strength.

For pesticide-free home growing, prioritise clean equipment, physical pest removal, insect exclusion and suitable biological controls.

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Growing References

• University of Florida, Arugula: Planting and Care
• North Carolina State University, Eruca vesicaria
• Cornell University, Arugula Growing Guide

Sources

• Cavarianni et al. (2008), Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution
• University of Florida, Arugula: Planting and Care
• North Carolina State University, Eruca vesicaria
• Cornell University, Arugula Growing Guide