Will Sunflower Seeds Grow Through Garden Paper & Mulch?

Garden Paper

• Garden paper blocks weed growth in garden beds. It provides impermanent weed control since it breaks down over the course of a year, so is best used on annual crops like sunflowers. Nearly any type of nontoxic paper works well as garden paper. Manufactured papers are typically black and come on rolls. Nonglossy newspaper pages also work well for blocking weeds. Lay them over the garden bed in layers three to four sheets thick. Sunflower seeds cannot penetrate garden paper when they sprout, so it's necessary to cut holes in the paper for each plant before sowing the seeds.

Mulch Choices

• Organic mulches, such as bark, wood chips and straw, work well for sunflowers. These mulches help retain soil moisture, block weeds and insulate the soil. The mulch adds nutrients to the soil when you till the mulch into the garden at the end of the growing season. Sunflower seeds may germinate through a thin layer of mulch, but the garden benefits most from a thicker layer that may inhibit germination. It's best to apply mulches after the seeds have sprouted.

Seeding Method

• Sunflower seeds take about 14 days to germinate and send up sprouts. Sow the seeds in spring after frost danger is past, otherwise a late spring frost may kill the tender young plants. Sow sunflower seeds 1/2 to 1 inch deep in moist, well-drained soil in a sunny area of the garden. Spacing depends on the mature size of the sunflower variety. Giants, which reach 6 feet or taller at maturity, require three-foot spacing. Shorter types, which typically grow between 1 and 3 feet tall, require spacing of one to two feet apart. Not all seeds germinate and grow successfully, so sow two seeds in each planting hole and thin out the weaker plants so the remaining plants are at the required spacing after the seeds sprout.

Applying Mulch

• Apply garden paper before you plant the sunflower seeds. Lay it over the bed, overlapping the edges so no soil shows between the sheets. Cut planting holes through the paper and sow the seeds in the soil beneath. The sunflowers sprout and grow through the holes, so the paper can't block germination. Keep the soil moist during germination and don't allow it to dry completely beneath the paper. The paper blocks weeds but doesn't block water. Once the sunflowers are 6 inches tall, apply the mulch on top of the paper. Use a 2-inch layer of mulch to provide the best weed suppression and moisture retention in the soil.