The whole of ecological system is benefited by Yajnya. For example, earthworms are able to generate more moisture to the soil due to performance of Yajnya. The Yajnya makes them happy and their hormone secretions increase, thereby benefiting the soil and therefore the plants that live in that soil.
If a Yajnya is going on all the 24 hours in proximity to a garden, that in itself is an effective aid to insect control. The atmosphere becomes saturated with ghee and the plants are able to manufacture a protective coating due to a special chemical combination in their chemical makeup interacting with the ghee absorbed by the plants by breathing. The Yajnya atmosphere also creates something intangible that permits this situation to occur which is based on the vibrational content of the atmosphere due to the Mantras going on all the time.
When growing plants in Agnihotra atmosphere do not necessarily expect the plants themselves to become large. Instead, observe the size, quality and appearance of the vegetables, fruit or flowers. All the energy of the plant goes towards yield as by performance of Yajnya we make the plants happy.
Lettuce, the vegetable, grown in Homa atmosphere, possesses great healing and revitalizing properties.