What actually Kausalya meant?

The suhag rath will be organized in line with some stars etc and just not on the day of wedding. The Purohit will check the auspicious day and time for the same and only on that prescribed night the couple shall become one.

Garbhadhana Samskara according to Vedas:

The ritual Garbhadana is called by Sankhayana Grihya Sutra as Chaturtikarma. It says that after three days have lapsed after the marriage ceremony on the fourth day the husband makes an offering of cooked food to eight deities, namely, Agni, Vayu, Surya, Aryaman, Varuna, Pusan, Prajapati and Svistakrt. He then pounds the root of ADHYANDA plant and extracting its juice pours it into the nostrils of his wife. Then just before consummating the union he touches her,with saying

The mouth of Gandharva Visvavasu art thou
Then he murmurs into her ears
Into the breath I put the sperm Oh! My ( he repeats the name of his wife)
Or he may repeat other verses prescribed.

The prayer mainly was for a male child. He may otherwise repeat verses from the Brihadaranya upanishad which say
As the earth has fire inside it, as heaven has Indira inside it, as the wind is inside ( as the embryo of) the quarters, so do I plant a Garbha in three, Oh! (he repeats the name of his wife). The upanishad also has passages to the effect that that after three days have lapsed after menstruation when the wife has taken her bath she pounds rice. It is then cooked together with various ingredients. The ingredients vary when the couple desire for a fair, dark, or brown son or a scholarly daughter. The husband then offers clarified butter through fire. He also eats a portion of the food prepared and gives some to his wife. He then sprinkles water on her thrice saying
Rise, Oh Visvavasu, seek another blooming girl with her husband. He embraces her and says :
I am Ama. Thou art Sa. Thou art Sa. I am Ama. I am the Saman. Thou art Rk. I am the sky, though art the earth. Come, let us strive together so that a male child may be born to us. Even as they unite he repeats mantras that mean .May Vishnu make ready your conception channel. May Tvasta frame your beauty. May Prajapati sprinkle and may Dhata implant an embryo into you. . Oh , Sinivali! Oh, Prthustuka! Implant embryo in her. May the two aswins who wear a garland of lotuses plant in thee an embryo., etc.

Atreya holds in Hiranyakesi Grihya Sutra that mantras were to be repeated at union between a husband and wife throughout life. Badarayana however says that this is necessary only when the union is first consummated, and when they unite again after each menstrual cycle. The Vaikhanasa Smarta Sutra calls this ceremony as RTUSAMGAMANA.