That is why contemplation of the seer is seedless or supportless samadhi.
Verse 45
सूक्ष्मविषयत्वम्चालिण्ग पर्यवसानम् ॥४५॥
sūkṣma-viṣayatvam-ca-aliṇga paryavasānam ॥45॥
The subtle objects end in Alingga - the unmanifested Prakriti.
Verse 46
ता एव सबीजस्समाधिः ॥४६॥
tā eva sabījas-samādhiḥ ॥46॥
The states of samadhi described in the previous sutras are dependent upon
a support or seed, and are termed sabija.
The gross objects are only the elements, and everything
manufactured out of them. The fine objects begin with the Tanmatras or fine particles. The organs, the mind , egoism, the mind-stuff (the cause of all manifestion) the equilibrium
state of Sattva, Rajas and Tamas materials—called Pradhana (chief), Prakrti (nature), or Avyakta (unmanifest), are all included within the category of fine objects.
The savitarka, nirvitarka, savicara, nirvicara, sananda and sasmita samadhis are known as sabija (seeded or with seed) samadhis.
All the states of samapatti described are seeded samadhis. All these samadhis are dependent upon an object which includes the intelligence (buddhi) and the 'I' principle. Their seed is the core of the being, the only seedless seat in each individual.
Through the disciplines of yoga, the sadhaka transforms his attention from the gross to the subtle. When he reaches the apex of nature, the mind being a part of nature, he attains perfection in controlling the modes of consciousness. He is able to stop all functions of the mind deliberate and non-deliberate, at will. That is why it is termed samadhi with seed.
Whatever is dependent on nature for contemplation is seeded samapatti.
The contemplation of the seer, who is the source of all seeds, is without support. Though both seer and nature are eternal, nature is changeable while the seer remains the same, immutable, not dependent on any support except his own self. That is why contemplation of the seer is seedless or supportless (nirbija) samadhi.
PATANJALI YOGA SUTRAS