Every year, there are materials and inputs that are used up through the normal course of producing a crop. Some supplies can be purchased in such quantities as to stretch over several years before requiring replenishment. Others must be tracked and replaced regularly, either due to the volumes of them that are used and the rate of depletion, or because they are perishable and cannot be held for an extended period.
Normal
In normal years, there might be rough and perhaps flexible timelines and deadlines for ordering product, in order to have it on hand when it is needed for the growing season (or whenever). You might order seeds or plant material of different types in the late fall, prior to winter settling in, with a fair bit of wiggle room and leniency from suppliers. You might order equipment parts, irrigation lines, plastic mulch, pots, trays, or other things at various times. You might feel fairly confident that you can make changes and adjustments to your plans, and still be able to make those come together and happen.
Current Reality
I think that we can safely say that we are not in normal times and will not likely return to them for some time. The current global situation has changed things not just at our local and regional levels, but also across the entire global supply chain. The entire world has had to shift and adjust to restrictions in moving products across borders that were almost a formality in the past. There are quarantine restrictions for many things, as well as innumerable other bottlenecks in the system. There are backlogs on many products.
Where previously you could be reasonably assured of finding a product from your normal supplier, chances are this year, things will be a bit different. This is due to changes (slowdowns) in the rate of delivery of both raw and finished products from other regions and countries. Some raw materials have been diverted away from areas like agricultural production, in order to supply the need for medical products or other products deemed higher priority.
So What?
I would say that taking a cautious-bordering-on-pessimistic-or-paranoid approach might be a good plan for this year. Make your plans and your orders as early as you can. In a best-case scenario, everything is smooth and golden, and you are ready to go ahead of schedule. At worst, you know where you stand well ahead of the season, and can make alternative arrangements, if necessary/possible. And if you have ordered first, you might well be at the front of the line.
In the end, what I am saying is that you need to plan ahead and assume that things are going to be more complicated, take longer and maybe be a bit harder (and more expensive) to source than they were in the past. Is that guaranteed? No, but it seems highly likely. So, do not leave things until later. If 2020 has taught us anything, it is that preparation is critical, and never as simple as it might have seemed at an earlier date.
Here are some wise words from some wise guys to inspire you away from procrastination.