Peter&rsquo;s 20-20-20. 1/2 Pound. General Purpose Water Soluble Fertilizer with Micro Nutrients. Picture showes 1 pound bag. this offer is for 1/2 pound. Great general purpose fertilizer for Orchids potted plants, landscape, trees, shrubs, vegetables ect. The original Peters. One of the most versatile products in the Peters line May be employed as a foliar spray and or drench plant/soil. Use for indoor and outdoor plants. For general purpose use mix 1 teaspoon per gallon of water. With soilless mixes, avoid using during extended cool, cloudy weather in late fall to early spring in northern climates