#49 - Apr 2021 - Garden Stuff - © - Sandy Lang - slang@xtra.co.nz
JUSTUS VON LIEBIG (1803-1873)May: Almost winter. Time to prune: remove dead wood, reshape, control size (see #16 & #17). Time to buy new trees/shrubs. Buy while garden centres have a good range of good plants. The first buyer gets the best plants - the last buyer gets the rejects. The rule is ‘buy now - plant later’ (in late winter). And talking of rules… The Law of Limiting Factors: Prof Liebig said, ‘Plant growth is controlled not by the total amount of resources but by the amount of the scarcest resource’. In other words, if a plant is short of light, giving it more water or more fertiliser won’t help. If it’s short of water, giving it more light or more fertiliser won’t help. If it’s short of a particular soil mineral, giving it more water, more light or even more of the other soil minerals won’t help. Sick plants: In general, a plant suffering a specific ‘resource limitation’ not only grows slowly but it is also more prone to attack by pests and diseases. But what’s limiting? Light? Wind? Water? One of the soil minerals? The difficult bit is identifying which resource is ‘limiting’. Fixing it is usually easy… Sunshine: Most plants like all-day sun. Almost all food plants like all-day sun. Most flowering plants like lots of sun. Shade-tolerant plants are mostly slow-growing, green and perennial (e.g., ferns). Wind: Plants don’t like wind, but some tolerate it (flaxes). I discussed wind shelter previously (see blog #2). Water: Too much water is as bad as too little water. Plants don’t like drought, but some tolerate it (olives). Plants don’t like waterlogging, but some tolerate it (willows). A sandy soil holds little water, so deep watering doesn’t work. In Eastbourne, water little and often. Use tree chip mulch to increase soil water-holding capacity and to reduce soil-surface evaporation in the summer months. Soil minerals: It’s hard to know which soil minerals are deficient. Leaf discolouration may be a guide but can be misleading. Soil and leaf analyses are expensive. Best to use a general ‘NPK’ fertiliser ‘with micronutrients’. Many NZ soils are low in some micronutrients, so the ‘limiting resource’ may well be one of these. A sandy soil is not good at holding mineral nutrients. In Eastbourne, fertilise little and often. A slow-release fertiliser is more expensive, but it does some of the work for you. ___________________________________
JUSTUS VON LIEBIG (1803-1873)May: Almost winter. Time to prune: remove dead wood, reshape, control size (see #16 & #17). Time to buy new trees/shrubs. Buy while garden centres have a good range of good plants. The first buyer gets the best plants - the last buyer gets the rejects. The rule is ‘buy now - plant later’ (in late winter). And talking of rules… The Law of Limiting Factors: Prof Liebig said, ‘Plant growth is controlled not by the total amount of resources but by the amount of the scarcest resource’. In other words, if a plant is short of light, giving it more water or more fertiliser won’t help. If it’s short of water, giving it more light or more fertiliser won’t help. If it’s short of a particular soil mineral, giving it more water, more light or even more of the other soil minerals won’t help. Sick plants: In general, a plant suffering a specific ‘resource limitation’ not only grows slowly but it is also more prone to attack by pests and diseases. But what’s limiting? Light? Wind? Water? One of the soil minerals? The difficult bit is identifying which resource is ‘limiting’. Fixing it is usually easy… Sunshine: Most plants like all-day sun. Almost all food plants like all-day sun. Most flowering plants like lots of sun. Shade-tolerant plants are mostly slow-growing, green and perennial (e.g., ferns). Wind: Plants don’t like wind, but some tolerate it (flaxes). I discussed wind shelter previously (see blog #2). Water: Too much water is as bad as too little water. Plants don’t like drought, but some tolerate it (olives). Plants don’t like waterlogging, but some tolerate it (willows). A sandy soil holds little water, so deep watering doesn’t work. In Eastbourne, water little and often. Use tree chip mulch to increase soil water-holding capacity and to reduce soil-surface evaporation in the summer months. Soil minerals: It’s hard to know which soil minerals are deficient. Leaf discolouration may be a guide but can be misleading. Soil and leaf analyses are expensive. Best to use a general ‘NPK’ fertiliser ‘with micronutrients’. Many NZ soils are low in some micronutrients, so the ‘limiting resource’ may well be one of these. A sandy soil is not good at holding mineral nutrients. In Eastbourne, fertilise little and often. A slow-release fertiliser is more expensive, but it does some of the work for you. ___________________________________