Planting Miscanthus

Initial ground assessment

Miscanthus x giganteus is a hardy perennial that can be harvested yearly, once the crop is established, for a number of saleable uses. Assessing the suitability of land for planting miscanthus or more specifically for  giant miscanthus, is essential in ensuring that the crop will grow and thrive as a long term source of sustainable income. Knowing when and where to plant the miscanthus crop is a primary consideration for the successful cultivation of a consistent long term return on investment.

The location of the land, the soil constitution, the climate throughout the year and the amount of available water will all assist in the decision making process. Optimisation of conditions for a good growth will be achieved in soil with a pH balance of between 5.5 and 7. Water is vital but overly wet conditions are not ideal and similarly a good level of sunshine and warmth in both the air and in the ground will contribute towards attaining a high level of annual return.

Wooded areas nearby the fields selected for growth can deprive sunlight if they cast shade across areas of the miscanthus. They may also deplete natural water levels in the soil as trees do take up a lot of the moisture out of their surrounding grounds. Other considerations should be made in assessing the environmental considerations of growing the crop as it can have a strong visual impact on the landscape but it should be noted that the introduction of miscanthus has normally had a very positive effect on the locality particularly for wildlife.

UK Conditions

For planting miscanthus, most agricultural land conditions within the UK will be good enough to grow the crop. Fields prone to regular flooding are not suitable. The climatic conditions in the more northerly parts of England and those of Scotland may be relatively limiting due to the cooler average temperatures but the crop should still grow to a harvestable size. Whilst the conditions may not be absolutely optimal for achieving the fullest attainable length of harvestable stems, the crop can still grow to a size that is economically viable. If average temperatures continue to rise due to the changes in conditions on a more global scale, this will become less of a factor. It should be borne in mind that ideal conditions are a combination of a number of elements and a small deficit in one should not be seen as a good reason not to grow the crop. Miscanthus is very resilient  and will grow in a wide range of conditions.

How to plant miscanthus giganteus

Once the land has been selected it should be sprayed with a suitable herbicide in the late autumn. This should kill off any fresh weeds that have taken root and will prepare the land for the necessary rotovating which is ideally done as soon as the soil starts to warm after the winter frosts. This will usually be late February or early March. A second spray of herbicide should be completed at this point. The best time to plant Miscanthus is late March/early April once the ground has recovered from the winter frosts and has been properly prepared.

Planting miscanthus will take the form of placing the rhizomes in the ground at a density of about 15,000 per hectare. Rhizomes should be well budded and spaced about 80cm apart from each other. One hectare is 100m by 100m so this size of area will be able to accommodate 125 plants in each line of 125 lines. This would give a field of 15,625 planted rhizomes.

Miscanthus rhizomes

Selecting fresh rhizomes with at least 2 or 3 buds and using standard potato planting equipment has historically resulted in at least a 90% success rate. The rhizomes will produce enough plant stems for a healthy harvest for many years to come. Once planted the soil should by compacted with a heavy roller.

When the miscanthus planting takes place at around the end of March, or slightly after if spring is late, it is at a depth of between 5cm and 10cm. This will allow the rhizomes to produce a few shoots each that will start to grow through the end of spring and the beginning of summer.

Once the miscanthus rhizomes are planted the shoots will take a few weeks to become visible. At this point any weeds could potentially be stronger than the budding miscanthus plants still at rhizome depth. A final spray of herbicide just after planting should protect the developing plants and allow them to naturally take over the land space.

Purchase of quality rhizome is essential, an area we can assist you with – contact Mike Cooper who will be happy to advise.

Rate of growth for miscanthus

How fast the miscanthus grows in the first summer is relatively not as quick as when the crop is mature. It will not reach harvestable heights at this early stage in the life cycle but will grow to between one to two metres in height in the first summer and will establish its presence in the ground as the dominant plant. The subsequent leaf litter that falls during late summer and autumn will form a protective layer of mulch which provides a natural prevention for the growth of future weeds. There is now no need for further herbicide spraying or any other chemical treatment although it is always worth checking that weeds and potential blight are not present through regular monitoring.

UK grants for miscanthus

The UK government is no longer accepting new projects under its energy crop scheme that is run by DEFRA. This ceased at the end of 2013. There is growing support that this, or a similar scheme, needs to be revived so although it means that there is currently no assistance for the planting of new bioenergy crops, this may well not be the case in the future.

Since the original introduction of the scheme the cost of planting contracts has dropped sufficiently so that there is far less need for a government grant and that the crop is economically viable on a stand-alone basis. However, it is in the country’s interest to successfully grow these types of crops so it is more than likely that the proposed reintroduction of the grant may be successful.