The research aims to study the effect of sugar palm dregs compost with cow rumen activator on sweet corn plant growth and to determine the effective consentration of cow rumen activator and dose of sugar palm dregs compost on sweet corn plant growth in coastal sandy soil of Samas Beach, Bantul. This research was conducted at Greenhouse and Field Experiment of Agriculture Faculty, Universitas Muhammadiyah Yogyakarta in November 2015 to August 2016. The research was done using an experimental method with single factor that were arranged in a Completely Randomized Design (CRD). The treatments were the dose of sugar palm dregs compost and various concentrations of cow rumen activators, which consists of 10 levels, i.e : 20 tons/hectare and 60%, 20 tons/hectare and 70%, 20 ton/hectare and 80%, 20 tons/hectare and 90%, 20 tons/hectare and 100%, 25 tons/hectare and 60%, 25 tons/hectare and 70%, 25 tons/hectare and 80%, 25 tons/hectare and 90% and 25 tons/hectare and 100%. Each treatment was repeated four times so the total are 40 experimental plants. The results showed that the sugar palm dregs compost on various concentration of cow rumen activator could improve vegetative growth of sweet corn plants in coastal sandy soil of Samas Beach, Bantul. All treatments had no significantly different effect to all plant parameters. Dose of 20 tons/hectare of sugar palm dregs compost using 60% concentration of cow rumen activator is the most effective on sweet corn plant growth in coastal sandy soil of Samas Beach, Bantul.