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Setting The Stage For Spring Production and A Successful Spring Fundraiser by Mike H.

Well, winter is here. The holidays are ahead and a much-deserved break is drawing near. Prior to that break just a bit of extra work, if not already taken care of, will help eliminate some of the stresses prior to and during the next growing season.


Hopefully your plants and supplies are already ordered and confirmed. If they aren’t, please act quickly as logistics, inventory and weather all complicate even the best laid of plans. I always advise shipping supplies in November or December so, if backorders exist, there is still ample time to receive everything prior to your plants arriving. You don’t want plants showing up before your growing supplies… Plant orders should be placed as well. If you wait until after the holidays you risk not getting what you want as most all plants are subject to availability from the breeding stations in Central and South America as well as lead times for the sowing/sticking of bare root cuttings which can be anywhere from five to ten weeks depending on the plant. There is still time to place these orders but please act now and not after the first of next year.

Can you use last year’s soil? Probably not, especially if it is from last spring. If your soil was received later in the year, chances are that it is probably good to use. Wetting agents are typically good for at least 6 months after soil is received. Depending on the manufacturing date, it may be good for up to a year. After that the ability for it to absorb water evenly throughout the mix lessens to where the mix will actually repel water. If you use an organic mix this timeline is even less due to the organic nature of the wetting agent which is usually yucca extract.

To easily find out if your existing soil is still good you can try this easy test. Take a handful of dry potting soil and place it in a bucket of water. If the dry soil has not taken moisture within a few minutes and is still floating on top, your soil mix will cause you problems. If it darkens with absorbed moisture it should be good to use. This is a good reason to buy just the soil needed for the next 6 months. If you buy too much and use off the pile during the course of the year, you risk this wetting agent going bad.

Greenhouse Checklist:

  • Your shade should be off the greenhouse. You’ll need as much light as possible reaching your plants well into the month of March. Snow can accumulate on the shade-cloth as well, putting extra weight on your greenhouse structure. Plants usually fare better without shade till sometime in the month of April. This can vary by the type of greenhouse, crops grown, region, etc.
  • Check your irrigation system and controls if you have them. Clean filter, check all emitters. It’s a good idea to have an extra solenoid on hand if your system uses them.
  • Check your environmental control system to make sure all louvers, heaters, fans and equipment work as they’re supposed to. Make sure you know what your day and night-time temperatures should be as these are key to growing a good spring crop.
  • Make sure you have HAF fans to circulate greenhouse air. Also make sure they’re operational and are oriented correctly. They should push air throughout the greenhouse in a rotating pattern. The importance of these fans is often overlooked. They destratify air layers, help prevent foliar diseases and, during daylight hours, will help your plants grow by moving air away from the leaves that has been depleted of carbon dioxide during photosynthesis. This air will then be replaced with fresh air that has a higher carbon dioxide content. Thus running these fans both day and night is a good practice unless your ventilation fans are on. It’s hard to have too much air movement.

Crop Scheduling:
It’s important to make sure your plants are the size you want for spring sale.

  • For hanging baskets bring in plants from the middle to end of February and use four plants per 10” basket for the best quality. Five to 6 plants do well in a 12” basket. • For 4” and 4.5” pots, schedule for the first week in March and use one rooted liner per pot.
  • For bedding flats, schedule plugs for the 3rd week in March
  • Many variables may affect this schedule such as your region, date of sale, market, and growing conditions. The above schedule works best for the Mid-west including the states of Missouri, Kansas, Indiana, Nebraska, etc.
  • The ultimate goal is to avoid too small or overgrown plants at the time of your sale.

Bugs! Always a concern… 

  • Bugs are not here because they’re easy to kill. They’re resilient, adaptive, often bullet-proof creatures that will be with us forever.
  • Prevention and early detection are best in preventing problems. Yellow Sticky cards and routine monitoring go far in detecting these pests before they become an issue.
  • Check under leaves and on new plant material especially on the newest growth. Most growers ship clean plant material but some harvest off of their own stock plants which can harbor such pests.
  • Avoid overwintering pet plants such as outdoor tropical hibiscus, palms and other ornamentals. If your principal wants a winter home for his/her hibiscus, please make the argument against it. These plants harbor just about any kind of insect/mite/pest you can imagine. Outdoors they are not really visible but once brought into the utopian greenhouse environment they’ll manifest themselves and spread, potentially to everything in your greenhouse.
  • If you have stock plants that you use for class projects, propagation, etc., please monitor carefully and routinely.
  • No weeds should be in the greenhouse. These are also sources of all kinds of insect pests.
  • Remove any algae or peat moss on walkways, along the edges of the greenhouse or in the gravel. This is very attractive to fungus gnats that will lay eggs in this media causing flying gnats in short order. Top-dress with fresh gravel to avoid this. If you have concrete floors this shouldn’t be a concern.
  • Consider beneficial insects. They are available now in smaller quantities and would make for a great class project. While conventional chemical controls do have their place, this would be a much easier/safer option in the school setting, especially with food crops and students in the greenhouse.


  • Spring crops are short term so it is best to keep your fertilizer regimen simple.
  • In most cases, the general purpose 20-10-20 is best with all peat based soil mixes. It is a formation made for growing where the often used 20-20-20 is useful primarily for maintenance. I know some still use this but better results should be seen with the 20-10-20.
  • When fertilizing it is best to apply with each irrigation at about 200 PPM if possible. Of course I know this may not be possible for all but it is much better to fertilize often as these plants are hungry and will develop much better with frequent/adequate nutrition.
  • Do not fertilize if dry. The salts in the fertilizer can injure dehydrated roots, causing leaf edge burn….or worse.


pH meter in Cup measure water on salad growing natural background. hydroponic vegetable garden farm.
  • If using a good fertilizer there are typically few pH issues with spring annuals since their crop time is relatively short. Most fertilizers acidify the irrigation water, which along with the soil pH of about 5.9, will keep the soil pH in the normal range for most plants. This reinforces the argument for fertilizing with each irrigation. Soil pH tends to drift up with most municipal waters that are typically very alkaline. Once that pH gets near 6.8, problems may develop.
  • Calibrachoas and petunias the first to show symptoms of this pH drift. They’re very sensitive to the diminished uptake of iron caused by high pH. They serve as that “canary in the goldmine” indicating a looming problem for other plants if not soon corrected.
  • This pH topic can be quite complicated but fortunately proper greenhouse practices can avoid most problems that may develop before becoming a real issue.
  • If you don’t already have one, please invest in a pH meter to keep an eye on your soil as well as an EC meter which will help you with your fertilizer rates. This routine testing would be a great project also for the students to take part in.

If you’re doing something different in your greenhouse than is shared above and all is going well, please don’t change. Perhaps modify, experiment and consider but be cautious before changing a good thing. Successful growing is the result of many, many variables. Some we have control over and some we don’t. The above is only meant as a guide or checklist prior to the upcoming growing season.

If you need help or elaboration on any of the above topics, please feel free to contact us. If you need a source for or advice on annuals, perennials, pH or EC meters, soil or anything else, I can help you with that as well.

Happy Growing!

Mike Hellmann
Plants and Cuttings Manager

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