Vigorous, young strawberry plants produce the best berries. As strawberry cropping slows, plants produce long horizontal stems (runners). Along each runner a small plantlet begins to form and tiny white roots will appear at the base – see photos below. Vigorous runners can produce two or three plantlets along each runner. If you remove mulch from the area under each new plantlet and anchor plantlets to the soil surface by placing a stone on the runner on the parent side of each plantlet, you can produce many new plants for your strawberry patch. Anchoring plantlets in this way allows the crown of the plantlet to sit on the soil surface. (Strawberry crowns will rot if buried.) If your strawberry bed contains plenty of organic matter, all you need to do is give the bed a drink of seaweed extract tea to stimulate root growth and build disease resistance, and keep the soil damp. Otherwise, add a handful of mature compost to the soil surface under each plantlet. Each parent plant will provide nourishment to the new plants until they develop enough roots to grow independently.
When plantlets are well established in autumn, the runners connecting them to the parent plant can be cut, and the new plants can be left where they are or transplanted to a new spot. Tip:While strawberries are still cropping, place a marker beside the plants that produce the best berries and only use the runners from these plants to improve the quality of produce in your strawberry patch.
For future reference, here are some general tips for growing strawberries.
• Strawberry plants should be replaced every 3 years as young plants are better croppers.
• The bed should be positioned where it receives winter sun, as shaded foliage in cool conditions does not dry quickly, and wet foliage encourages the establishment of several diseases.
• Choose a bed that that is rich in organic matter and has not contained any of the tomato/potato family for 3 years.
• Prepare the strawberry bed in early to mid summer with compost and well-rotted manure covered with a thick layer of mulch. Compost has a pH close to neutral and the break down of the manure will make soil slightly more acid, which strawberries prefer.
• If you don’t have a lot of compost to spare, starting preparing the bed in early summer by sheet composting manure (without lime) under a thick layer of mulch. Strawberry plants respond well to organic cultivation as beneficial fungi in organic matter help keep soil diseases under control and provide roots with nutrients.
• In autumn, plant out strawberry runners from only healthy plants that have produced well. I find that Full Moon phase is best for planting out strawberry crowns. See post on Propagating strawberries
• I don’t recommend growing strawberries in beds covered with black plastic. Strawberries need regular watering, and an occasional dose of liquid fertiliser applied to soil. A plastic soil covering requires drip irrigation to be set up before planting. The plastic not only makes it difficult to apply supplementary fertilisers and clear blocked drippers, it also gets very hot and can also burn fruit in many areas of Australia.
• Manures will provide the nutrients the crowns need for strong roots and good foliage growth. Good foliage cover is important to protect fruit from birds. If growth seems slow, an application or two of weak manure tea will help. But, don’t overdo it. Excess nitrogen will attract aphids that carry virus disease.
• In warm climates, plants will grow quickly and produce fruit through the cooler months. In warm temperate, temperate and cooler climates, fruit is produced through spring or summer. In cold areas, plants can be protected from frost by covering them with clean straw.
• When flowers start to form an application of seaweed extract tea will help both fruit quality and disease protection. Several flowers will produced at the end of stout stems, which stand above the foliage. If plants have produced good foliage, after flowers are pollinated, the weight of the fruit will gradually bend the stems until the berries are protected by the foliage.
• Excess watering as fruit forms will result in watery strawberries.
• If you have not mulched the bed to conserve moisture, clean straw or wood shavings should be placed under developing fruit to keep it clean.
Our strawberries are producing exceptionally well this year. So far, they have supplied a steady crop, and a couple of times I’ve harvested 3 kilos in a week from our 1 x 2.5 metre patch, – and that doesn’t include the ones that the slugs have dined on. (I’ve been so busy I haven’t got around to putting in a couple of beer traps yet.) The patch has produced far too many strawberries for us, and the excess has been made into jam, or frozen (in 500g batches) for strawberry daiquiris at Christmas or for further batches of jam. When I prepare our next strawberry bed, I will make it smaller because the grandchildren now have their own strawberry patch.
I’ve had several questions recently about growing strawberries. In cool and temperate areas, strawberries are fruiting or coming into fruit while in warmer climates strawberries produce best through the cooler months. At this time of year, there are a few things you can do to improve the quality of your strawberry crop.
• Maintain regular deep watering – but don’t over-water fruiting plants – use the finger test to check soil dampness.
• Pick fruit regularly. Rotting fruit encourages disease.
• Place a plant marker beside the best producers so that you can take runners from the healthiest plants when cropping finishes.
• If you notice fruit is becoming sunburned, you can set up a tent fly of 30-50 percent shadecloth to protect fruit from the sun during the hottest part of the day. The fly has to be high enough to allow good air circulation, or foliage diseases can occur. The tent fly also deters birds that love eating strawberries.
• A drink of seaweed extract tea, applied to the soil around the plants will build resistance to disease and improve the quality of fruit.
• If plants have leaf spot, remove and dispose of damaged leaves in a sealed plastic bag, then spray foliage mid morning with one cup of strained chamomile tea diluted to 500 ml. and, in future, only water plants early in the day.
• Add a couple of beer traps if snails or slugs are a problem. See Snails and slugs
You can start preparing next year’s strawberry bed next month, and I will post some tips on getting the best out of your strawberry bed.