Effect of Substrate Stratification Without Fine Pine Bark Particles on Growth of Common Nursery Weed Species and Container-grown Ornamental Species

Substrate stratification is a new research area in which multiple substrates, or the same substrate with differing physical properties, are layered within container to accomplish production goal, such as decreasing water use, nutrient leaching, potentially reducing weed growth. Previous using pine ( Pinus sp.) bark screened ?1/2 3/4 inch reduced growth of bittercress Cardamine flexuosa ) by 80% 97%, whereas liverwort Marchantia polymorpha coverage was 95% 99%. The objective this study evaluate remove all fine particles top strata and determine its effect on common nursery weeds ornamental plants. Stratified treatments consisted either 1/8 1/4 inch, 1/2 3/8 applied at depths 1 2 inches standard ?1/2-inch substrate. An industry-standard treatment also included not stratified but only throughout container. A controlled-release fertilizer incorporated bottom (no media), industry had throughout. Compared nonstratified standard, decreased spotted spurge Euphorbia maculata counts 30% 84% 57% 94% after seeding containers. shoot dry weight 14% 55%, 71% 93% treatments. Liverwort nearly 100% substrate, ligustrum Ligustrum japonicum up 20%, no differences were observed index, nor any blue plumbago Plumbago auriculata ).