For a good preservation, parsley needs pre-cooling. Stored at low temperatures (-1, -2 or -3ºC) and 95% of relative humidity it may be kept up to two months.

It is important to lower the temperature very quick in order to diminish the metabolic activity of the parsley, as well as of other leaf vegetables, so as to improve their conservation. During transport, a usual technique in the United States is the application of ice to cool the vegetable down, although it is not used in Europe. Parsley can also be subject to vacuum pre-cooling, since the characteristics concerning the relation leaf surface/volume allow to do so, although it is not profitable due to the quantities handled.

Along with temperature, the relative humidity has an effect on the time of conservation. The parsley can be stored from 1 to 3 weeks with ice; at temperatures between -1 and 0ºC and 95% of relative humidity the period may extend to 2 months. It is even possible to preserve them at -2 or -3ºC in order to maintain the aroma.

By regulating the levels of oxygen and carbon dioxide (8-10%) in the atmosphere, that is to say, with controlled atmosphere, there is an improvement of the conservation, although at commercial level this method is hardly used.

The parsley may loose commercial value due to the attack of pests such as leafminers, aphids, etc. and diseases like mildew and other fungi.

The parsley may be attacked by several pests that affect other vegetables like carrots, celery, etc. (the celery miner, different aphids and others) and diseases such as the carrots mildew, septoria of the celery and that caused by the fungus Cercospora petroselini, producing some brown spots on the leaves.