Nitrogen Deficiency in Plants: Symptoms, Causes & Treatment

A primary driver of plant growth and colour, Nitrogen (N) is the mineral required in the highest quantities for normal plant growth. When supply runs short, plants quickly lose vigour and marketability.

Read on to learn what symptoms to look out for when N is in short supply, and why winter/spring is a particularly important time to be vigilant.

Nitrogen Deficiency in Philadelphus

Nitrogen Deficiency Symptoms in Plants – spot the early warning signs

• Yellowing of older leaves (chlorosis), starting at tips and margins
• Reduced growth and smaller plants, with shorter internodes
• Delayed flowering and fruiting, impacting crop timing
• Weak, spindly stems, with plants turning pale in severe cases

Early intervention preserves quality and avoids lost sales opportunities.

Nitrogen Deficiency in Doronicum

Why Nitrogen Deficiency risks rise in Winter and Spring

Nitrogen deficiency often develops over winter when controlled-release fertilisers reach the end of their longevity – such as with unplanned, over-wintered stock. In outdoor stock water-soluble feeds can be easily leached in wet weather, which there are limited water-soluble feeding opportunities in indoor crops when grown drier.

This means crops, particularly imported stock where water-solubles are often used – frequently arrive in early spring already short of nitrogen and slow to respond without corrective action.

How to manage Nitrogen Deficiency in plants

• For crops that start to run out of Nitrogen in winter, topdressing in early spring is a great way for quick greening up, helping to kick start early season sales: OsmoTop 2-3M (22-5-10) or Osmocote Topdress FT 4-5M (22-5-6 + 2MgO + TE)

• For Nitrogen deficiency during the active growing season, use fast acting Peters Professional Foliar Feed (27-15-12 +TE), Universol Green (23+6+10 +2MgO +TE) water soluble fertliser – or its hard or soft water versions – Universol HW 211 (23-10-10+2MgO+TE) or Universol SW 312R (18-7-12+6CaO+2MgO).

How to Prevent Nitrogen Deficiency in Growing Media

It is important to start with the right nitrogen level in your growing media, aligned to crop cycle and species. This needs to be adjusted for peat-reduced or peat-free mixes, where nitrogen availability can be more limited. To reduce leaching losses from base fertilisers (particularly calcium nitrate) ICL offers new, slow or controlled-release nitrogen options:

• Osmoform High N (8-10 weeks) security.
• Osmocote N (5-6 month) controlled supply.

Get technical support for Nitrogen Deficiency

To guard against Nitrogen deficiency, or to rectify an issue in your crop, reach out to ICL who will be happy to help.

Nitrogen Deficiency in Guzmania ‘Ostara’