From Seedling to Fruit
- Once your seedling is in the ground, it is very vulnerable to the elements, even inside your coldframe. Pumpkin plants do not like extreme heat and will not tolerate the cold. Therefor you need to do everything you can to keep the plant happy. At night in May, place a bucket or a box over your plant and cover with a blanket to retain as much of the day’s warmth as possible. Uncover in the morning when the temperature is above 40 outside or 50 inside the coldframe.
- Water your seedling as needed to keep the soil moist but not wet. Luke warm water is better than cold for watering.
- Your plant is susceptible to disease through its lifespan. One of the most common is known as Powdery Mildew, identified by the presence of white powdery looking spots on the top and bottom of leaves. Spraying your plant once a week with a fungicide such as Daconil will go far in keeping disease at bay. Insects are also a problem such as slugs, cucumber bugs and white flies. A pesticide such as Liquid Sevin applied once a week opposite of the fungicide application should keep the bugs down. As with all pesticides and fungicides, use caution and follow the manufactures label. Apply chemicals only after the plant is well established in the ground and then only lightly until the plant begins to ‘vine-out’.
- Your plant should start to vine in about 2-3 weeks, depending on the temperature and soil moisture. If your plant decides it wants to vine in the wrong direction, you can turn it in the right direction over the course of a couple weeks using a few stakes and moving the vine a little bit each day during the heat of the day, starting when the vine is about 12' to 18' long. At around 5 weeks old, your plant vine will grow up to 1 foot a day so be prepared to stay on top of it from this point on.
- As your vine grows, it will sprout what are known as secondary vines off of the main vine. These secondaries are where the plant gets much of its energy and should be nurtured as the main vine is. However, off these secondaries will grow more vines known as tertiary vines or sucker vines. These vines rob the plant of valuable nutrients and should be pinched off when they appear.
- Your plant can cover up more than 1000 square feet if left to grow unbridled so things need to be done so your plant doesn’t become a ‘jungle’ of vines running every which way. Establishing a growing pattern for your plant is first. There are several growing patterns that growers use but the most widely used pattern is the so-called ‘Christmas Tree’. Think of your plant as a christmas tree, where the main vine is the trunk and the secondaries are branches. Train your vines so that the main vine runs generally straight out from the stump and the secondaries grow perpendicular to the main as shown below:
If you do not have enough room to grow your plant in the pattern above, you can cut off all the secondaries from one side, allowing the main and remaining secondaries to be a bit longer. This is known as the flag pattern. In either case, your main vine should be allowed to grow to a minimum length of 15 feet, although 20’ or more is better. Your secondaries should be allowed to grow to a minimum length of 10 feet using the christmas tree pattern and 14 feet using the flag pattern. Whatever pattern you decide on, your chances of growing a big pumpkin will be much better if you strive for a plant that covers 400 square feet or more of area. Pruning is a vital part of the overall health of the plant. It not only keeps the vines contained within the space you have to grow in, but it improves air circulation for drying the plant surface to prevent conditions favorable to disease. When the vines reach the perimeter of the patch, simply pinch off the very end of new growth on the vine and bury the end, keeping in mind the optimum lengths listed above. Some growers cut off every other secondary along the main vine to provide more space for the remaining vines to have room to grow. This does take away some potential energy production from the plant, so it may be beneficial to allow the main vine to grow a bit longer to compensate.
- When you walk in your patch, avoid soil compaction by using boards to walk on and plan your routes so you don’t have to move the boards around as much to tend your plant and fruit.
- Giant pumpkin plants have the ability to grow 2 tap roots where every leaf stock meets the vine. These tap roots can supply a larger volume of nutrients to your plant and roots than just the main root system alone. Most every grower that has produced a big pumpkin practice the method of trenching in front of all the vines on the plant and burying them just below the surface, keeping ahead of the plant as it grows. This provides the tap roots an easier growing medium is generally accepted to be a much more productive method. It’s a lot of work but growing a pumpkin over 500 Lbs. is no easy task.
- Giant pumpkins have nutrient requirements that change over the lifespan of the plant. That is not to say that you need to fertilize continuously. Fertilizer needs depends on your soil conditions and the needs of the plant. You will learn with experience how to ‘read the plant’ and react to it’s needs. The first 3 weeks the plant requires more phosphorus for root growth. From week 3 to 6 the plant needs more nitrogen to encourage vine and leaf growth. From week 6 to the time you pollinate your first fruit, phosphorus is required again to encourage flowering. From July 1 to about July 20, no additional fertilizers or liquid fertilizers should be applied to avoid your young fruit from aborting. From July 20 to October, potassium becomes the main nutrient to encourage fruit growth. Pumpkins also can draw nutrients through the leaves of the plant. The majority of growers today foliar feed their plants with a liquid seaweed or fish and seaweed fertilizer. This not only feeds the plant but can help fight disease. It can be applied 2 to 3 times a week.
- Pumpkins require huge amounts of water, 623 gals a week or more if your plant takes up 1000 square feet. Remember to water at a constant rate and compensate for rain so the soil stays moist but not wet.