Jam, you are supposed to have at least 32PARwatts per ftsq.

This will prevent excessive stretching of internodes as all plants will be provided with sufficient light energy so plants will develop buds rather than growig tall.

hps light has 30%PAR efficency, so 1 sq ft must be lighted by 97watts hps. For best results you must goal for 42 PAR watts per sqft which is 126watts of hps light per sqft.

Your plants got streched because that light in the cupboard is insufficient for that qantity of plants, if you don't wish to improve lighting then you should consider growing 3-5 plants.